An Accurate Prediction of the pH Change Due to Degradation: Correction for a “Produced” Secondary Buffering System

Esmolol hydrochloride degrades in aqueous solutions by the hydrolysis of a labile aliphatic carboxy-ester group. The products are methanol and ASL-8123. The resulting aliphatic carboxylic acid moiety (ASL-8123) has a pK of 4.80, which is within 1 pH unit of the pH of the formulation. ASL-8123 therefore acts as a secondary buffer and minimizes the change in pH due to degradation. Equations are presented to calculate the change in the pH when the primary degradation product acts as a secondary buffer. This information can be used in the development of a parenteral product to predict, a priori, the concentration of buffer necessary for optimal pH maintenance. This knowledge can reduce the number of formulation screens required to determine the necessary buffer capacity for optimal drug stability.     

Surgery in Jehovah’s Witnesses

This is a retrospective study of the outcome of surgical procedures in patients who were Jehovah's Witnesses. Over a 75-month period, 58 Jehovah's Witness patients had 78 surgical procedures at the Vancouver General Hospital. Three patients had preexisting anaemia of less than 100 g.L-1 haemoglobin. Postoperative haemoglobin concentration decreased below 50 g.L-1 in three patients. One patient had a postoperative haemoglobin of 34 g.L-1 (haematocrit 10.1 per cent) and survived. One patient died from uncontrollable postoperative haemorrhage. Perioperative morbidity was not uncommon, including significant hypotension (eight cases), cardiac arrhythmias (six), myocardial ischaemia (three), excessive bleeding (four), postoperative nausea or syncope (four), and wound or urinary tract infection (four).     

A Decline in C6 Antibody Titer Occurs in Successfully Treated Patients with Culture-Confirmed Early Localized or Early Disseminated Lyme Borreliosis

C₆, a Borrelia burgdorferi-derived peptide, is used as the antigen in the C₆-Lyme disease diagnostic test. We assessed retrospectively whether a fourfold decrease or a decrease to a negative value in anti-C₆ antibody titer is positively correlated with a positive response to treatment in a sample of culture-confirmed patients with either early localized (single erythema migrans [EM]; n = 93) or early disseminated (multiple EM; n = 27) disease. All of these patients had been treated with antibiotics and were free of disease within 6 to 12 months of follow-up. Results show that a serum specimen taken at this time was either C₆ negative or had a ≥4-fold decrease in C₆ antibody titer with respect to a specimen taken at baseline (or during the early convalescent period if the baseline specimen was C₆ negative) for all of the multiple-EM patients (P < 0.0001) and in 89% of the single-EM patients (P < 0.0001). These results indicate that a decline in anti-C₆ antibody titer coincides with effective antimicrobial therapy in patients with early localized or early disseminated Lyme borreliosis.     

An efficient method for cloning human autoantigen-specific T cells

T-cell clones are valuable tools for investigating T-cell specificity in infectious, autoimmune and malignant diseases. T cells specific for clinically-relevant autoantigens are difficult to clone using traditional methods. Here we describe an efficient method for cloning human autoantigen-specific CD4+ T cells pre-labelled with CFSE. Proliferating, antigen-responsive CD4+ cells were identified flow cytometrically by their reduction in CFSE staining and single cells were sorted into separate wells. The conditions (cytokines, mitogens and tissue culture plates) for raising T-cell clones were optimised. Media supplemented with IL-2+IL-4 supported growth of the largest number of antigen-specific clones. Three mitogens, PHA, anti-CD3 and anti-CD3+anti-CD28, each stimulated the growth of similar numbers of antigen-specific clones. Cloning efficiency was similar in flat- and round-bottom plates. Based on these findings, IL-2+IL-4, anti-CD3 and round-bottom plates were used to clone FACS-sorted autoantigen-specific CFSE-labelled CD4+ T cells. Sixty proinsulin- and 47 glutamic acid decarboxylase-specific clones were obtained from six and two donors, respectively. In conclusion, the CFSE-based method is ideal for cloning rare, autoantigen-specific, human CD4+ T cells.     

Reconstitution of a functional interleukin (IL)-7 receptor demonstrates that the IL-2 receptor γ chain is required for IL-7 signal transduction

The interleukin (IL)-2 receptor γ chain has recently been shown to be a component of the IL-7 and IL-4 receptors. Using a transient transfection assay and the trans-activation of reporter gene constructs which are under the control of cytokine-responsive promoter elements, we have studied signal transduction through the IL-7 receptor (IL-7R). The reporter gene expression was not stimulated by receptors that contained the cytoplasmic domain of the IL-7R, either as intact IL-7R or as part of a chimeric receptor. However, co-expression of the IL-7R with the IL-2 receptor γ chain was able to stimulate gene activation. For maximal stimulation the intact cytoplasmic domains of each chain was required.     

T cell developmental defects in 'viable motheaten' mice deficient in SHP-1 protein-tyrosine phosphatase. Developmental defects are corrected in vitro in the presence of normal hematopoietic-origin stromal cells and in vivo by exogenous IL-7

Defects in the gene that encodes SHP-1 protein tyrosine phosphatase result in multiple hematopoietic abnormalities and generalized autoimmunity in viable motheaten (me(v)) mice. These mice also exhibit early thymic involution and abnormalities in T cell development. Here, we describe the use of fetal thymic organ culture (FTOC) and bone marrow adoptive transfer to study the effects of SHP-1 deficiency on thymocyte development. Chimeric FTOC established with normal bone marrow placed onto deoxyguanosine-treated fetal thymic lobes or onto scid fetal thymic lobes generated T cells. Bone marrow from SHP-1-deficient me(v)/ me(v) mice generated decreased numbers of T cells in chimeric FTOC established using deoxyguanosine-treated thymi but generated normal numbers in chimeric FTOC established using scid thymi. However, scid fetal thymi seeded with me(v)/ me(v) bone marrow also exhibited morphological abnormalities and contained elevated numbers of macrophages. Addition of IL-7 to me(v)/ me(v) bone marrow-seeded scid FTOC led to increased cell numbers, particularly of macrophages. Intrathymic injection of IL-7 partially restored the ability of progenitor cells in me(v)/ me(v) bone marrow to populate the thymus of adoptive recipients. We conclude that abnormal T cell development in me(v)/ me(v) mice may in part be due to defects in the ability of bone marrow-derived accessory cells to provide bioavailable IL-7 to developing thymocytes.     

Effect of hypothermia on renal sodium reabsorption

Summary The relationship between sodium reabsorption and oxygen consumption was studied in an isolated rabbit kidney preparation perfused with blood at 37, 28 and 19° C. When the temperature was lowered from 37° C to 28° C and to 19°C the rate of oxygen consumption and of the maximal P.A.H. excretion (Tm P.A.H.) decreased more than that of sodium reabsorption.TheQ ₁₀ for sodium reabsorption is about 1.8, while that for maximal P.A.H. excretion is 2.5. Some hypothesis on the possible mechanisms of the lowQ ₁₀ of the Na⁺ reabsorption are forwarded.Preliminary reports have been published [Boll. Soc. Ital. Biol. Sper.43, 1019–1023 (1966) and44, 1784–1787 (1967);45, 860–862 (1969) and45, 863–865 (1969)].