The prevalence of glaucoma in a population-based study of Hispanic subjects: Proyecto VER

OBJECTIVE

To determine the prevalence of glaucoma in a population-based sample of Hispanic adults older than 40 years.

METHODS

Using 1990 census data for Arizona, groups of persons living in sections of the city in Nogales and Tucson were randomly selected with a probability proportional to the Hispanic population older than 40 years. We tried to recruit all eligible adults in homes with 1 self-described Hispanic adult. Detailed ocular examinations at a local clinic included visual acuity testing, applanation tonometry, gonioscopy, an optic disc evaluation, and a threshold visual field test. Open-angle glaucoma (OAG) was defined using a proposed international system for prevalence surveys, including threshold visual field defect and optic disc damage. Angle-closure glaucoma was defined as bilateral appositional angle closure, combined with optic nerve damage (judged by field and disc as for OAG).

RESULTS

Examinations were conducted in 72% (4774/6658) of eligible persons, with a 1.97% prevalence (95% confidence interval, 1.58%-2.36%) of OAG (94 persons). The age-specific OAG prevalence increased nonlinearly from 0.50% in those aged 41 to 49 years to 12.63% in those 80 years and older. Angle-closure glaucoma was detected in 5 persons (0.10%). Sex, blood pressure, and cigarette smoking were not significant OAG risk factors. Only 36 (38%) of the 94 persons with OAG were aware of their OAG before the study. Screening results with an intraocular pressure higher than 22 mm Hg (in the eye with a higher pressure) would miss 80% of the OAG cases.

CONCLUSIONS

The prevalence of OAG in Hispanic persons was intermediate between reported values for white and black persons. The prevalence increased more quickly with increasing age than in other ethnic groups. Glaucoma was the leading cause of bilateral blindness.

Caspase-9 and APAF-1 form an active holoenzyme

Autocatalytic activation of initiator caspases is the link between pro-apoptotic signals and the destruction machinery of apoptosis. Activation of caspase-9, which mediates oncogene and drug-induced apoptosis, requires binding to the protein APAF-1. We found that the proteolytic activity of caspase-9 in a complex with APAF-1 is several orders of magnitude higher than that of the free enzyme. Thus, this complex functions as a holoenzyme in which caspase-9 is the catalytic subunit and APAF-1 its allosteric regulator. We argue that caspase-9 is activated by allosteric regulation and suggest that this mechanism is common for other initiator caspases.

The Nature of the Metal-Metal Bond in Bimetallic Surfaces

The formation of a surface metal-metal bond can produce large perturbations in the electronic, chemical, and catalytic properties of a metal. Recent studies indicate that charge transfer is an important component in surface metal-metal bonds that involve dissimilar elements. The larger the charge transfer, the stronger the cohesive energy of the bimetallic bond. On a surface, the formation of a heteronuclear metal-metal bond induces a flow of electron density toward the element with the larger fraction of empty states in its valence band. This behavior is completely contrary to that observed in bulk alloys, indicating that the nature of a heteronuclear metal-metal bond depends strongly on the structural geometry of the bimetallic system.

Role of ligaments and facets in lumbar spinal stability

STUDY DESIGN

The issue of segmental stability using finite element analysis was studied. Effect of ligament and facet (total and partial) removal and their geometry on segment response were studied from the viewpoint of stability.

OBJECTIVES

To predict factors that may be linked to the cause of rotational instabilities, spondylolisthesis, retrospondylolisthesis, and stenosis.

SUMMARY OF BACKGROUND DATA

The study provides a comprehensive study on the role of facets and ligaments and their geometry in preserving segmental stability. No previous biomechanical study has explored these issues in detail.

METHODS

Three-dimensional nonlinear finite element analysis was performed on L3-L4 motion segments, with and without posterior elements (ligaments and facets), subjected to sagittal moments. Effects of ligament and facet (partial and total) removal and their orientations on segment response are examined from the viewpoint of stability.

RESULTS

Ligaments play an important role in resisting flexion rotation and posterior shear whereas facets are mainly responsible for preventing large extension rotation and anterior displacement. Facet loads and stresses are high under large extension and anterior shear loading. Unlike total facetectomy, selective removal of facets does not compromise segmental stability. Facet loads are dependent on spatial orientation.

CONCLUSIONS

Rotational instability in flexion or posterior displacement (retrospondylolisthesis) is unlikely without prior damage of ligaments, whereas instability in extension rotation or forward displacement (spondylolisthesis) is unlikely before facet degeneration or removal. The facet stress and displacement distribution predicts that facet osteoarthritis or hypertrophy leading to spinal stenosis is most likely under flexion-anterior shear loading. Selective facetectomy may restore spinal canal size without compromising the stability of the segment. A facet that is more sagittally oriented may be linked to the cause of spondylolisthesis, whereas a less transversely oriented facet joint may be linked to rotational instabilities in extension.

Penaeidins, a new family of antimicrobial peptides isolated from the shrimp Penaeus vannamei (Decapoda)

We report here the isolation of three members of a new family of antimicrobial peptides from the hemolymph of shrimps Penaeus vannamei in which immune response has not been experimentally induced. The three molecules display antimicrobial activity against fungi and bacteria with a predominant activity against Gram-positive bacteria. The complete sequences of these peptides were determined by a combination of enzymatic cleavages, Edman degradation, mass spectrometry, and cDNA cloning using a hemocyte cDNA library. The mature molecules (50 and 62 residues) are characterized by an NH2-terminal domain rich in proline residues and a COOH-terminal domain containing three intramolecular disulfide bridges. One of these molecules is post-translationally modified by a pyroglutamic acid at the first position. Comparison of the data obtained from the cDNA clones and mass spectrometry showed that two of these peptides are probably COOH-terminally amidated by elimination of a glycine residue. These molecules with no evident homology to other hitherto described antimicrobial peptides were named penaeidins.

Structure-based inhibitors of tau aggregation

Aggregated tau protein is associated with over 20 neurological disorders, which include Alzheimer's disease. Previous work has shown that tau's sequence segments VQIINK and VQIVYK drive its aggregation, but inhibitors based on the structure of the VQIVYK segment only partially inhibit full-length tau aggregation and are ineffective at inhibiting seeding by full-length fibrils. Here we show that the VQIINK segment is the more powerful driver of tau aggregation. Two structures of this segment determined by the cryo-electron microscopy method micro-electron diffraction explain its dominant influence on tau aggregation. Of practical significance, the structures lead to the design of inhibitors that not only inhibit tau aggregation but also inhibit the ability of exogenous full-length tau fibrils to seed intracellular tau in HEK293 biosensor cells into amyloid. We also raise the possibility that the two VQIINK structures represent amyloid polymorphs of tau that may account for a subset of prion-like strains of tau.

ESMO Consensus conferences: guidelines on malignant lymphoma. part 2: marginal zone lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma

To complement the existing treatment guidelines for all tumour types, ESMO organizes consensus conferences to focus on specific issues in each type of tumour. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, next to the 11th International Conference on Malignant Lymphoma. The conference convened ∼30 experts from all around Europe, and selected six lymphoma entities to be addressed; for each of them, three to five open questions were to be addressed by the experts. For each question, a recommendation should be given by the panel, referring to the strength of the recommendation based on the level of evidence. This consensus report focuses on the three less common lymphoproliferative malignancies: marginal zone lymphoma, mantle cell lymphoma, and peripheral T-cell lymphomas. A first report had focused on diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia.

Differential effects of tobacco and alcohol in cancer of the larynx, pharynx, and mouth

Two thousand five hundred forty male patients with cancer of larynx, pharynx, and mouth were examined in the same hospital between 1975 and 1982. Different sites were compared according to alcohol and tobacco consumption: oropharynx, hypopharynx, larynx supraglottis, larynxglottis, epilarynx, lip, tongue-tip, and tongue lateral border, other tongue sites, gum, floor of the mouth, and buccal mucosa. For tobacco, the mean daily consumption of smokers and exsmokers did not differ according to location (except in patients with cancer of the lip, in whom the consumption was lowest). Cancer locations differed significantly according to the daily alcohol consumption. The consumption was the lowest for patients with cancer of the lips and the glottis, the highest for patients with cancer of the epilarynx, hypopharynx, and the floor of the mouth. Significant differences were observed in the percentage of nonsmokers or nondrinkers, even between adjacent locations: supraglottis versus glottis; tongue, tip, and lateral border versus tongue, other sites; floor of the mouth versus buccal mucosa. Some of the results might be particular to elements of the French life-style (e.g., consumption of brown tobacco, high consumption of wine).

Dismantling cell-cell contacts during apoptosis is coupled to a caspase-dependent proteolytic cleavage of beta-catenin

Cell death by apoptosis is a tightly regulated process that requires coordinated modification in cellular architecture. The caspase protease family has been shown to play a key role in apoptosis. Here we report that specific and ordered changes in the actin cytoskeleton take place during apoptosis. In this context, we have dissected one of the first hallmarks in cell death, represented by the severing of contacts among neighboring cells. More specifically, we provide demonstration for the mechanism that could contribute to the disassembly of cytoskeletal organization at cell-cell adhesion. In fact, beta-catenin, a known regulator of cell-cell adhesion, is proteolytically processed in different cell types after induction of apoptosis. Caspase-3 (cpp32/apopain/yama) cleaves in vitro translated beta-catenin into a form which is similar in size to that observed in cells undergoing apoptosis. beta-Catenin cleavage, during apoptosis in vivo and after caspase-3 treatment in vitro, removes the amino- and carboxy-terminal regions of the protein. The resulting beta-catenin product is unable to bind alpha-catenin that is responsible for actin filament binding and organization. This evidence indicates that connection with actin filaments organized at cell-cell contacts could be dismantled during apoptosis. Our observations suggest that caspases orchestrate the specific and sequential changes in the actin cytoskeleton occurring during cell death via cleavage of different regulators of the microfilament system.

A systematic density functional theory study of the electronic structure of bulk and (001) surface of transition-metals carbides

A systematic study of the bulk and surface geometrical and electronic properties of a series of transition-metal carbides (TMC with TM = Ti, V, Zr, Nb, Mo, Hf, Ta, and W) by first-principles methods is presented. It is shown that in these materials the chemical bonding is strongly covalent, the cohesive energies being directly related to the bonding-antibonding gap although the shift of the center of the C(2s) band related peak in the density of states with respect to diamond indicates that some metal to carbon charge transfer does also take place. The (001) face of these metal carbides exhibits a noticeable surface rumpling which grows along the series. It is shown that neglecting surface relaxation results in very large errors on the surface energy and work function. The surface formation induces a significant shift of electronic energy levels with respect to the corresponding values in the bulk. The extent and nature of the shift can be understood from simple bonding-antibonding arguments and is enhanced by the structural rippling of this surface.

Autosomal dominant sectoral retinitis pigmentosa. Two families with transversion mutation in codon 23 of rhodopsin

A cytosine-to-adenine transversion in codon 23 of rhodopsin, the rod visual pigment gene, was reported recently by Dryja et al in 17 of 148 unrelated patients with autosomal dominant retinitis pigmentosa, but the clinical findings associated with this deletion have not been reported in detail. In screening our patients with autosomal dominant retinitis pigmentosa for the codon 23 transversion, we found positive results in four affected individuals from two families with sectoral retinitis pigmentosa, while 12 patients with sectoral retinitis pigmentosa from different families had negative results, suggesting that other gene sites or locations may give this same phenotypic change. From our patients' history of light exposure and the location of degeneration in the retina, we hypothesize that light phototoxicity may be playing an expressive role in this point mutation of the rhodopsin gene. This is the first report in which a type of retinitis pigmentosa has been associated with a specific molecular gene defect, although the actual pathophysiologic mechanism currently is unknown.

Correction of limb-length inequality during total hip arthroplasty

Although several methods of intraoperative limb-length measurements have been described, their success in predicting the limb-length correction is not well documented. A new technique of measuring intraoperative limb lengthening using a vertical Steinmann pin at the infracotyloid groove of the acetabulum was studied in 100 consecutive primary total hip arthroplasties. Correlation of the predicted intraoperative correction was done with the postoperative radiographic measurements. Preoperative limb-length inequality ranged from -24 mm (short) to +2 mm (long) (mean, -4.2 mm). Intraoperative measurement of lengthening ranged from 0 to 15 mm (mean, 5.9 mm). Radiographic measurements of postoperative radiographs showed lengthening ranging from 0 to 17 mm (mean, 7.4 mm). There was significant correlation between the 2 values (r =.84). Postoperative limb-length inequality ranged from -7 mm to +8 mm (mean, 1.9 mm). None of the patients had to use shoe lifts for equalization of limb lengths.

Penaeidins, antimicrobial peptides with chitin-binding activity, are produced and stored in shrimp granulocytes and released after microbial challenge

Penaeidins are members of a new family of antimicrobial peptides isolated from a crustacean, which present both Gram-positive antibacterial and antifungal activities. We have studied the localization of synthesis and storage of penaeidins in the shrimp Penaeus vannamei. The distribution of penaeidin transcripts and peptides in various tissues reveals that penaeidins are constitutively synthesized and stored in the shrimp haemocytes. It was shown by immunocytochemistry, at both optical and ultrastructural levels, that the peptides are localized in granulocyte cytoplasmic granules. The expression and localization of penaeidins were further analysed in shrimp subjected to microbial challenge. We found that (1) penaeidin mRNA levels decrease in circulating haemocytes in the first 3 hours following stimulation and (2) an increase in plasma penaeidin concentration occurs after microbial challenge, together with (3) a penaeidin immunoreactivity in cuticular tissue, which can be related to the chitin-binding activity we demonstrate here for penaeidins.

Oncogene-dependent apoptosis is mediated by caspase-9

Understanding how oncogenic transformation sensitizes cells to apoptosis may provide a strategy to kill tumor cells selectively. We previously developed a cell-free system that recapitulates oncogene dependent apoptosis as reflected by activation of caspases, the core of the apoptotic machinery. Here, we show that this activation requires a previously identified apoptosis-promoting complex consisting of caspase-9, APAF-1, and cytochrome c. As predicted by the in vitro system, preventing caspase-9 activation blocked drug-induced apoptosis in cells sensitized by E1A, an adenoviral oncogene. Oncogenes, such as E1A, appear to facilitate caspase-9 activation by several mechanisms, including the control of cytochrome c release from the mitochondria.

Characterisation of shrimp haemocytes and plasma components by monoclonal antibodies

Various haemolymph components of the shrimp Penaeus japonicus were identified and characterised by monoclonal antibodies. Three groups of monoclonal antibodies were raised. Their reactivity to haemocyte types and/or secreted molecules was determined by immunofluorescence and the molecular masses of the antigens were analysed by western-blotting. A 170 kDa protein, in reducing conditions, was recognized by four panhaemocytic monoclonal antibodies from group 1. This protein was present both in the plasma and in the haemocytes from which it appears to be secreted. The shrimp haemocytes were separated by isopycnic centrifugation on a Percoll gradient and the different subpopulations were antigenically analysed using the two monoclonal antibodies, 40E2-2A and 40E10-2B, from group 2. The granular cells were labelled by 40E2-2A which was specific for a protein of 142 kDa also present in plasma. By comparison, the 40E10-2B monoclonal antibody was assumed to be the marker for small hyaline and semigranular cells since the granular ones were not labelled. Moreover, the antigen immunoprecipitated by this monoclonal antibody was shown to have different molecular masses of 250, 150, 66 and 27 kDa under nonreducing conditions. It appeared to be secreted by the haemocytes. Some plasma proteins were recognized by the third group of monoclonal antibodies. The antibodies, designated 41D11-3A, 42C11-3B and 42E8-3C, all immunoprecipitated a protein with an apparent molecular mass of 180 kDa under reduced conditions. The 44E6-3D antibody was specific for a 75 kDa protein under reduced conditions and was shown to be immunoreactive against P. japonicus haemocyanin extract.(ABSTRACT TRUNCATED AT 250 WORDS)

Incorporation of L-tyrosine, L-phenylalanine and L-3,4-dihydroxyphenylalanine as single units into rat brain tubulin

The product of the incorporation of [14C]tyrosine as single unit into a protein of the soluble fraction of rat brain homogenate was purified by following a procedure used to purify tubulin. Sodium dodecylsulphate-polyacrylamide gel electrophoresis of the purified material showed a single protein band containing all the radioactivity. Purification data indicate that this protein accounts for 10.2% of the total protein of the supernatant fraction. This is in good agreement with the amount found for tubulin by the [3H]colchicine-binding method (10.5% of the total protein). The incorporated [14C]-tyrosine was found in the alpha-subunit of tubulin. Protein labelled with [3H]colchicine and [14C]tyrosine was precipatated with vinblastine sulphate and the radioactivity of 3H and that of 14C were quantitatively recovered in the precipitate (98%). Sodium dodecylsulphate-polyacrylamide gel electrophoresis of the vinblastine precipitate showed that the 14C radioactivity moved with the tubulin band. Results obtained in experiments with phenylalanine and 3,4-dihydroxyphenylalanine were identical to those obtained for tyrosine. Bineing of colchicine did not interfere with the incorporation of tyrosine. About 30% of tubulin from rat brain supernatant fraction can incorporate tyrosine as single unit.

Cell wall composition of the yeast and mycelial forms of Paracoccidioides brasiliensis

Isolation and chemical analyses of the cell walls of the yeast (Y form) and mycelial forms (M form) of Paracoccidioides brasiliensis and Blastomyces dermatitidis revealed that their chemical composition is similar and depends on the form. Lipids, chitin, glucans, and proteins are the main constituents of the cell walls of both forms of these fungi. There is no significant difference in the amount of lipids (5 to 10%) and glucans (36 to 47%) contained by the two forms. In both fungi, the Y form has a larger amount of chitin (37 to 48%) than the M form (7 to 18%), whereas the M form has a larger amount of proteins (24 to 41%) than the Y form (7 to 14%). Several properties of the glucan of P. brasiliensis were studied. Almost all of the glucan in the Y form was soluble in 1 n NaOH, was weakly positive in the periodic acid-Schiff reaction, was not hydrolyzed by snail digestive juice, and had alpha-glycosidic linkage. Glucans of the M form were divided into alkali-soluble (60 to 65%) and alkali-insoluble (35 to 40%) types. The alkali-soluble glucan was similar to that of the Y form; the alkali-insoluble glucan was positive in the periodic acid-Schiff reaction and was hydrolyzed by snail digestive juice.

Oral alendronate induces progressive increases in bone mass of the spine, hip, and total body over 3 years in postmenopausal women with osteoporosis

To determine the effects of long-term daily oral alendronate sodium (ALN) on bone mass in postmenopausal women with osteoporosis, 19 centers enrolled 516 postmenopausal women aged 45-80 years with spine bone mineral density (BMD) at least 2.5 SD below the mean for young premenopausal women in a 3-year, double-blind, placebo-controlled study. Subjects were randomly allocated to one of four treatment groups: placebo; alendronate, 5 or 10 mg/day for 3 years; or alendronate, 20 mg/day for 2 years followed by 5 mg/day for the 3rd year. All patients received 500 mg/day of supplemental calcium to ensure adequate calcium intake. BMD was measured by dual-energy X-ray absorptiometry at several skeletal sites. Nonsignificant mean decreases in BMD of the spine, femoral neck, and trochanter of 0.6, 0.7, and 0.4%, respectively, occurred in the placebo group at 3 years. Relative to placebo-treated patients, spine BMD increased by 5.4%, 7.4%, and 8.4% in the 5, 10, and 20/5 mg ALN groups, respectively. Increases at the femoral neck were 3.5%, 5.5%, and 4.3%, and those at the trochanter were 5.1%, 7.2%, and 7.2%, respectively. Thus, efficacy of 10 and 20/5 mg ALN was similar, whereas the 5 mg dose was less effective. BMD continued to increase over the entire 3-year study duration in the ALN-treated groups and, compared with the other dosage groups, 10 mg ALN produced the largest gains in BMD during the 3rd year. Changes in biochemical markers of bone turnover and mineral homeostasis confirmed the effect of ALN to decrease bone turnover to a new steady-state level. The safety and tolerability of ALN were comparable with those of placebo. In summary, 10 mg daily oral ALN given for 3 years significantly and progressively increases bone mass and is a generally well-tolerated treatment for osteoporosis in postmenopausal women.

Blockade of tumor necrosis factor reduces lipopolysaccharide lethality, but not the lethality of cecal ligation and puncture

Inhibition of tumor necrosis factor (TNF) bioactivity has afforded protection in several animal models of sepsis. We examined whether inhibition of TNF could improve survival after lethal lipopolysaccharide (LPS) or cecal ligation and puncture (CLP) in CD-1 or BALB/c mice. Neutralizing rabbit anti-TNF antisera were evaluated in CD-1 mice by injecting the antisera 3 h before intravenous (i.v.) LPS (600 micrograms). Implantable radiotransmitters were used for continuous monitoring of temperature. No decrease in mortality was observed, and the anti-TNF failed to prevent the drop in temperature. In BALB/c mice injected with antisera before LPS (200 micrograms) mortality was reduced (dead/total: control sera, 14/14; anti-TNF, 4/12; p = .007 control sera vs. anti-TNF). CD-1 mice were pretreated with anti-TNF or control sera; CLP was performed followed by administration of antibiotics. Anti-TNF did not decrease pulmonary neutrophil sequestration, improve survival, or prevent the decrease in temperature observed as sepsis developed. CLP was performed in the BALB/c mice using antibiotics plus anti-TNF antisera, but no protection was observed. Our results demonstrate that anti-TNF treatment prevents LPS mortality only when using certain strains of mice and inhibition of TNF fails to reduce mortality in a more clinically relevant model of sepsis.

Morphological effects of the nanostructured ceria support on the activity and stability of CuO/CeO2 catalysts for the water-gas shift reaction

Three CuO/CeO2 catalyst with different morphologies of ceria, namely nanospheres, nanorods and nanocubes, were synthesized and used to catalyze the water-gas shift (WGS) reaction. The reactivity tests showed that the Cu supported on the ceria nanospheres exhibited both the highest activity and superior stability when compared with the nanocube and nanorod ceria catalysts. Operando X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) methods were used to characterize these catalysts in their working state. High resolution electron microscopy (HRTEM, STEM) was used to look at the local atomic structure and nano-scale morphology. Our results show that the morphology of the ceria support, which can involve different crystal faces and concentrations of defects and imperfections, has a critical impact on the catalytic properties and influences: (1) the dispersion of CuO in the as-synthesized catalyst; (2) the particle size of metallic Cu upon reduction during the WGS reaction, (3) the stability of the metallic Cu upon variations of temperature, and (4) the dissociation of water on the ceria support. The nanosphere ceria catalyst showed an excellent water dissociation capability, the best dispersion of Cu and a strong Cu-Ce interaction, therefore delivering the best performance among the three WGS catalysts. The metallic Cu, which is the active species during the WGS reaction, was more stabilized on the nanospheres than on the nanorods and nanocubes and thus led to a better stability of the nanosphere catalyst than the other two architectures. Each catalyst exhibited a distinctive line-shape in the 800-1600 cm(-1) region of the DRIFTS spectra, pointing to the existence of different types of carbonate or carboxylate species as surface intermediates for the WGS.

N doping of TiO2(110): Photoemission and density-functional studies

The electronic properties of N-doped rutile TiO2(110) have been investigated using synchrotron-based photoemission and density-functional calculations. The doping via N2+ ion bombardment leads to the implantation of N atoms (approximately 5% saturation concentration) that coexist with O vacancies. Ti 2p core level spectra show the formation of Ti3+ and a second partially reduced Ti species with oxidation states between +4 and +3. The valence region of the TiO(2-x)N(y)(110) systems exhibits a broad peak for Ti3+ near the Fermi level and N-induced features above the O 2p valence band that shift the edge up by approximately 0.5 eV. The magnitude of this shift is consistent with the "redshift" observed in the ultraviolet spectrum of N-doped TiO2. The experimental and theoretical results show the existence of attractive interactions between the dopant and O vacancies. First, the presence of N embedded in the surface layer reduces the formation energy of O vacancies. Second, the existence of O vacancies stabilizes the N impurities with respect to N2(g) formation. When oxygen vacancies and N impurities are together there is an electron transfer from the higher energy 3d band of Ti3+ to the lower energy 2p band of the N(2-) impurities.

Enhanced Production of Monomeric Interferon-β by CHO Cells through the Control of Culture Conditions

The enhancement of recombinant protein expression of a transfected cell line is essential for the development of an efficient large-scale bioprocess. The effect of various media additives and temperature conditions were studied in an attempt to optimize protein production, stability, and protein glycosylation from a Chinese hamster ovary (CHO) cell line producing human beta-interferon (Hu-beta-IFN). We observed a decrease in the ELISA response of the glycoprotein in the later stages of batch cultures, which was attributed to molecular aggregation. Cells were subjected to various concentrations of glycerol, dimethyl sulfoxide (DMSO), and sodium butyrate (NaBu) in a variety of culture systems and conditions. The addition of both NaBu and DMSO resulted in higher specific productivities but reduced growth rates that resulted in a net reduction of interferon produced. Glycerol appeared to stabilize the secreted beta-IFN, resulting in reduced aggregation, despite a decrease in cell growth rate. Glycosylation analysis of isolated beta-IFN showed a time-dependent decrease in sialylation in batch culture that was ameliorated by the presence of glycerol. Low-temperature conditions (30 degrees C) had the greatest effect on productivity with a significant increase in beta-IFN titer as well as a reduction in the degree of molecular aggregation.