Tonsils, obesity and obstructive sleep apnoea.

In this article the normal effects of anaesthesia on breathing are defined. Specific threats to the airway are identified and illustrated by reference to common clinical conditions.     

Changes in metabolic rates and blood respiratory characteristics during pouch development of a marsupial, Macropus eugenii

Oxygen levels in the pouch of the tammar wallaby, Macropus eugenii, have been related to the metabolic rate of the young at pouch temperatures and the oxygen transport characteristics of its haemoglobin. Until 100 days of age, pouch young show mass-specific rates of oxygen consumption lower than predicted on the basis of body mass. This contrasts with data presented for laboratory mice. Oxygen levels in the pouch approximate atmospheric levels for the first 20 days and at times approaching pouch evacuation at 200 days. However, levels of around 17-18% occur at about the mid-point of pouch life. The oxygen-haemoglobin equilibrium curve shows a high P50 (up to 50 Torr at 36 degrees C) in the neonate, but after 2-3 weeks of age levels drop to those representative of the adult. Concentrations of 2,3-diphosphoglycerate in early pouch young are higher than in the adult animal and peak at around 30 mumol/g Hb. There is a significant decrease in the concentration of this compound with the age of the young.     

A novel 37-Kd adhesive membrane protein from cloned murine bone marrow stromal cells and cloned murine hematopoietic progenitor cells

The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells.