Expression of the a1-proteinase inhibitor (a1PI) gene was studied in human mononuclear cells. Using RNA blot and dot hybridization, a1PI mRNA was detected in human peripheral blood monocytes, bronchoalveolar and breast milk macrophages, but not in B or T lymphocytes. Using incorporation of a radiolabeled amino acid precursor, synthesis and secretion of a1PI were demonstrated in human monocytes and macrophages, but not in lymphocytes. In addition, a1PI was secreted in functionally active form as shown by complexing with serine proteases. Biosynthesis of a1PI by mononuclear phagocytes was greatest during the first 24 hr in culture and progressively decreased over the next 10 days. The reduction in a1PI biosynthesis in vitro involved a mechanism acting at the pretranslational level as a1PI mRNA content also progressively declined over 10 days in culture. The ease of sampling human monocytes and macrophages now permits examination of the biochemical defect in homozygous PiZ and PiS a1PI deficiencies and study of the functional significance of locally produced aIPI in normal tissues and sites of injury or inflammation.a1-proteinase inhibitor (a1PI), a single-chain 55-kDa glycoprotein, is a major serine proteinase inhibitor in human plasma. It is characterized by a remarkable degree of polymorphic variition. Two of the variants, PiZ a1PI and PiS a1PI, are associated with moderately to severely diminished plasma levels and, in many cases, the development of chronic disease in liver and/or lung (1-3).Although it is generally considered a tissue-specific product of the liver, several recent studies have suggested that a1PI is also produced by human mononuclear cells (4-8).Other plasma proteins, including many of the complement proteins, a-2-macroglobulin, lysozyme, and plasminogen activator, that are predominantly synthesized by the liver are also synthesized by monocytes and macrophages, and the products are thought to have important functions in regulation of local tissue injury (9-13). Unfortunately, technical limitations in separation of mononuclear cell subpopulations, biosynthetic labeling, and analytical methods in previous reports (4-8) have prevented definitive identification of a1PI biosynthesis in human mononuclear cells. In the present study, we provide evidence for transcription of the aPI gene and translation, postsynthetic processing, and secretion of a1PI in a functionally active form in human peripheral blood monocytes, bronchoalveolar and breast milk macrophages, but not in B or T lymphocytes. MATERIALSDulbecco's modified Eagle's medium (DME medium), DME medium lacking methionine, RPMI 1640 medium, RPMI 1640 lacking methionine, Hanks' balanced salt solution, and fetal bovine serum were purchased from GIBCO and medium 199 was from M. A. Bioproducts (Walkersville, MD).[35S]Methionine (specific radioactivity, -1000 Ci/mmol; 1 Ci = 37 GBq) and [32P]deoxycytidine triphosphate (specific radioactivity, =3000 Ci/mmol) were obtained from New England Nuclear and 14C-methylated protein standards were from ...

We altered the concentration of plasma proteins in human blood in vitro by adding solutions with [Na+], [K+], and [Cl-] resembling those in normal blood plasma, either protein-free or with a high concentration of human albumin. After equilibrating the samples with a gas containing 5% CO2-12% O2-83% N2 at 37 degrees C, we measured pH, PCO2, and PO2; in separated plasma, we determined the concentrations of total plasma proteins and albumin and of the completely dissociated electrolytes (strong cations Na+, K+, Mg2+ and anions Cl-, citrate3-). With PCO2 nearly constant (mean = 35.5 Torr; coefficient of variation = 0.02), lowering plasma protein concentration produced a metabolic alkalosis, whereas increasing plasma albumin concentration gave rise to a metabolic acidosis. These acid-base disturbances occurred independently of a minor variation in the balance between the sums of strong cations and anions. We quantified the dependence of several acid-base variables in plasma on albumin (or total protein) concentration. Normal plasma proteins are weak nonvolatile acids. Although their concentration is not regulated as part of acid-base homeostasis, hypoproteinemia and hyperalbuminemia per se produce alkalosis and acidosis, respectively.

Asthmatic patients who came to hospital for treatment of severe attacks were assessed for level of obstruction and the effects of a deep inhalation (DI) on degree of obstruction at various stages of their treatment and after recovery over several days. The more severe the obstruction, the greater was the constrictor effect of a DI; as lung function improved with intensive treatment, including corticosteroids, the constrictor effect diminished. Thus, we believe the constrictor effects of a DI relate to the degree of inflammation in the obstructive process. These longitudinal data relating severity to the effects of a DI were nearly identical to previously published cross-sectional data in a group of patients with spontaneous asthma with widely different levels of lung function. It is possible that the response to a DI in a given asthmatic subject serves as a functional marker for the predominant mechanism for obstruction.

No abstract

To determine the basis for low serum con-