DFP Labeling of Platelets During Recovery from Thrombocytopenia

Rat platelets were labeled with tritiated diisopropylfluorophosphate(³H-DFP) during recovery from acute thrombocytopenia. The results indicated that there was significant labeling of megakaryocytes by ³H-DFPwhich, in the presence of an increased rate of platelet production, resulted inmaintenance of relatively constant values for platelet-bound radioactivity during the period of maximum platelet production and reactive thrombocytosis.Significant random loss of platelets was apparent, and, when a cohort ofyoung platelets was transfused to normal recipients, they were destroyed at anormal rate.

     

Synthesis of thymosin α1 by fragment condensation using tert.-butyl side chain protection

A novel synthesis of thymosin α₁ by classical methods using seven tert. -butyl side chain protected fragments is described. Optimum conditions were found for the final DCC/HOBt coupling of the two key intermediates; decapeptide and octadecapeptide. Thymosin α₁ was purified by two stages of preparative HPLC (partial purification with C₈ and final purification with C₁₈ reverse phase silica gel) to give a 30% overall yield for the final four stages of synthesis (including catalytic hydrogenation of octadecapeptide, coupling, deprotection and purification). The product was shown to be homogeneous by thin-layer and paper high voltage electrophoresis, isoelectric focusing analysis, thin-layer chromatography and high performance liquid chromatography. Amino acid analysis, optical rotation, ¹ H-n.m.r. spectroscopy, FAB mass spectroscopy and peptide mapping after tryptic digestion confirmed the structure of thymosin α₁. Three minor stereoisomer contaminants were isolated by HPLC and characterized as [D-Lys¹⁴]-thymosin α₁, [D-Lys¹⁷]-thymosin α₁ and [D-Ala³]-thymosin α₁ resulting from racemization at Lys¹⁴, Lys¹⁷ and Ala³ during the coupling of the fragments. A final contaminant, isolated by HPLC, was characterized as N^α-isobutyloxycarbonyl-thymosin α₁ (15–28), which results from “wrong way opening” of an activated mixed anhydride.     

The significance of fat-filled macrophages in the diagnosis of aspiration associated with gastro-oesophageal reflux

Tracheal aspirates from 46 children were examined for the presence of fat-filled macrophages. They had no history suggestive of gastro-oesophageal reflux. The number of positive results from this group (46%) was compared with the number of positive results (73%) in a group of 40 children with proven gastro-oesophageal reflux. The difference in proportion of positive results between the two groups was statistically significant ( P <0.05). In addition, subgroups of subjects, negative for gastro-oesophageal reflux and lower respiratory tract disease, were compared with children who had both conditions. A slightly greater difference, although at a similar level of significance, was found. The fact that 42% of subjects without lower respiratory tract disease or gastro-oesophageal reflux had tracheal aspirates positive for fat-filled macrophages would, however, suggest that this test is of limited clinical value and may need better quantitation before it can be recommended for widespread clinical use.     

THE EFFECT ON GROWTH OF CHILDHOOD ASTHMA

ABSTRACT. Martin, A. J., Landau, L. I. and Phelan, P. D. (Department of Thoracic Medicine, Royal Children's Hospital, Melbourne, Australia). The effect on growth of childhood asthma. Acta Paediatr Scand, 70:683,.–The effect on growth of asthma has been documented in a prospective study from age 7 to 21 years in a randomly selected group of 342 subjects. These subjects covered the whole spectrum of childhood wheezing. Growth suppression was first noted at 10 years of age in the more severely affected groups and was most marked at 14 years of age. By 21 years of age, all groups had achieved a height and weight not significantly different from control subjects. Growth delay occurred in children with more persistent asthma even if they had never received oral corticosteroid therapy but growth was more delayed in those receiving oral steroids. The effect of steroids was most significant in those with frequent episodic asthma whose asthma alone was probably not sufficiently severe to retard growth.     

The Impact of Discussion of Non-Medical Problems in the Physician's Office

Martin FJ, Bass MJ. The impact of discussion of non-medicalproblems in the physician's office. Family Practice 1989; 6:254–258. To determine the impact of discussion of non-medical problemswith the physician, patients with at least one chronic illnesswho were taking medication were interviewed in their familydoctor's office. Of 149 patients interviewed, 90.6% reportedat least one non-medical problem. Half (51%) of those patientswith a problem had discussed it with their doctor. More thanhalf (55%) of those patients discussing a problem reported thatthe discussion was helpful. Patient compliance and satisfactionwere positively associated with ‘helpful’ discussion,but not with discussion per Se. In particular, the two aspectsof doctor-patient communication which were significantly associatedwith feeling helped were: ‘Doctor tells me all I wantto know about my illness’ and ‘Doctor gives me achance to say what is really on my mind’. Both factorsreflect care which is oriented to patient concerns. The studyresults provide support for a patient-centred approach to care.