Plasma immunoreactive melanotrophic hormones in patients on maintenance haemodialysis.

Circulating levels of melanotrophic horomones and ACTH were determined in patients treated by maintenance dialysis for chronic renal failure. Plasma melanotrophic hormone levels were greatly increased in all patients studied (125-1100 ng/1 as compared with 12-36 ng/1 in normal adults) and were correlated with the duration of treatment. Skin pigmentation, especially in exposed areas, was notably increased, particularly in those patients with the highest plasma melanotrophic concentrations. Plasma ACTH levels were normal or only slightly raised and circulating corticosteroid concentrations, as determined by a fluorimetric method, all lay within the physiological range. The dissociation between ACTH and melanotrophic hormone levels in these patients may have been the result of a slower metabolic clearance of the latter.     

Clobetasone butyrate,a new topical corticosteroid: clinical activity and effects on pituitary-adrenal axis function and model of epidermal atrophy.

Clobetasone butyrate is a new corticosteroid, selected for study because of its combination of good activity in the vasoconstriction test and low systemic activity in animals. Formulated as an 0.05% ointment and cream (Molivate) it was clinically effective in patients with eczema, its activity being significantly greater than that of hydrocortisone 1% or fluocortolone 0.2% (Ultradil). Under conditions that predispose to maximal percutaneous absorption clobetasone butyrate ointment had minimal effect on hypothalamic-pituitary-adrenal function. In an animal model of cutaneous atrophy it caused less thinning of the epidermis than steroids other than hydrocortisone. Clobetasone butyrate 0.05% ointment and cream gave every indication of offering clinically effective topical anti-inflammatory activity with a wide margin of safety.     

Abdominal surgical emergencies in the puerperium.

Since surgical emergencies in the puerperium are rare, surgeons and obstetricians amass little experience of them. There may be considerable delay in making a diagnosis, firstly, because the abdominal symptoms are thought to be related to the pregnancy, and, secondly, because the signs are rarely convincing in contrast to the symptoms. Any of the common surgical emergencies may occur in pregnancy and the puerperium and there are some others that appear to be a particullar problem of the puerperium.     

Recombinant human albumin supports single cell cloning of CHO cells in chemically defined media

Biologic drugs, such as monoclonal antibodies, are commonly made using mammalian cells in culture. The cell lines used for manufacturing should ideally be clonal, meaning derived from a single cell, which represents a technically challenging process. Fetal bovine serum is often used to support low cell density cultures, however, from a regulatory perspective, it is preferable to avoid animal‐derived components to increase process consistency and reduce the risk of contamination from adventitious agents. Chinese hamster ovary (CHO) cells are the most widely used cell line in industry and a large number of serum‐free, protein‐free, and fully chemically defined growth media are commercially available, although these media alone do not readily support efficient single cell cloning. In this work, we have developed a simple, fully defined, single‐cell cloning media, specifically for CHO cells, using commercially available reagents. Our results show that a 1:1 mixture of CD‐CHO? and DMEM/F12 supplemented with 1.5 g/L of recombinant albumin (Albucult®) supports single cell cloning. This formulation can support recovery of single cells in 43% of cultures compared to 62% in the presence of serum. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

New concepts for rapid yeast settling. II. pH switching with an inert powder

A new technique is outlined for the rapid settling of yeast cells in fermentation media. The technique involved the addition of dense, inert particles (nickel powder) to a yeast suspension (Saccharomyces cerevisiae) at pH 4.5 and a rapid change of pH to 8.0-9.0. When the pH was changed large flocs formed immediately and settled rapidly, leaving a clear supernatant. On returning the pH to 4.5 the flocs were destroyed. This technique gave larger flocs and higher settling rates than the constant pH method, and much lower nickel/yeast ratios were required. Good flocculation also occurred in a fermentation medium. The technique was used to recycle yeast cells to a semicontinuous ethanol fermentation. Application of the technique to this and similar systems is discussed. The factors affecting yeast/inert powder flocculation are also discussed and a model is proposed to explain the observed experimental behavior for flocculation with a rapid change in pH.     

The fermentation stoichiometry of Thermotoga neapolitana and influence of temperature,oxygen, and pH on hydrogen production

The hyperthermophilic bacterium, Thermotoga neapolitana, has potential for use in biological hydrogen (H₂) production. The objectives of this study were to (1) determine the fermentation stoichiometry of Thermotoga neapolitana and examine H₂ production at various growth temperatures, (2) investigate the effect of oxygen (O₂) on H₂ production, and (3) determine the cause of glucose consumption inhibition. Batch fermentation experiments were conducted at temperatures of 60, 65, 70, 77, and 85°C to determine product yield coefficients and volumetric productivity rates. Yield coefficients did not show significant changes with respect to growth temperature and the rate of H₂ production reached maximum levels in both the 77°C and 85°C experiments. The fermentation stoichiometry for T. neapolitana at 85°C was 3.8 mol H₂, 2 mol CO₂, 1.8 mol acetate, and 0.1 mol lactate produced per mol of glucose consumed. Under microaerobic conditions H₂ production did not increase when compared to anaerobic conditions, which supports other evidence in the literature that T. neapolitana does not produce H₂ through microaerobic metabolism. Glucose consumption was inhibited by a decrease in pH. When pH was adjusted with buffer addition cultures completely consumed available glucose. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

A novel surface protein of Trichomonas vaginalis is regulated independently by low iron and contact with vaginal epithelial cells

Background  

Trichomonosis caused by Trichomonas vaginalis is the number one, non-viral sexually transmitted disease (STD) that affects more than 250 million people worldwide. Immunoglobulin A (IgA) has been implicated in resistance to mucosal infections by pathogens. No reports are available of IgA-reactive proteins and the role, if any, of this class of antibody in the control of this STD. The availability of an IgA monoclonal antibody (mAb) immunoreactive to trichomonads by whole cell (WC)-ELISA prompted us to characterize the IgA-reactive protein of T. vaginalis.     

P450 BM3: the very model of a modern flavocytochrome

Flavocytochrome P450 BM3 is a bacterial P450 system in which a fatty acid hydroxylase P450 is fused to a mammalian-like diflavin NADPH-P450 reductase in a single polypeptide. The enzyme is soluble (unlike mammalian P450 redox systems) and its fusion arrangement affords it the highest catalytic activity of any P450 mono-oxygenase. This article discusses the fundamental properties of P450 BM3 and how progress with this model P450 has affected our comprehension of P450 systems in general.     

Studies of heterogeneous mitochondrial populations in a mouse cell line: the effects of selection for or against mitochondrial genomes that confer chloramphenicol resistance

A single nucleotide substitution in a highly conserved region of the mitochondrial genome of a mouse cell line confers both chloramphenicol resistance and an alteration to the recognition site for the endonuclease Eco RV. This has enabled a detailed study on the effects of selection on a mitochondrial population comprising initially both chloramphenicol-resistant and chloramphenicol-sensitive mitochondrial genomes. The mutation confers advantage to cells grown in the presence of chloramphenicol, but is apparently deleterious in its absence. Selection at the cellular level is sufficient to explain the results observed. Fixation, which results in cells having mitochondria of only a single type, is slow. It is probable, therefore, that mammalian oocyte mitochondria are derived from only a small number of progenitors. This would allow fixation of new mutations and explain the observed uniformity in mitochondrial genomes of the individual in the presence of extensive variation between different members of the population.     

Phylogenetic analysis of the tenascin gene family: evidence of origin early in the chordate lineage

Background  

Tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. In order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate Ciona intestinalis, the pufferfish Tetraodon nigroviridis and Takifugu rubripes and the frog Xenopus tropicalis were identified and their gene organization and predicted protein products compared with the previously characterized tenascins of amniotes.