Biological variations of lysozyme concentration in the tear fluids of healthy persons.

Abstract

Lysozyme, discovered by Fleming,' is widely distributed in nature. It has been found in measurable quantity in tears, saliva, serum, nasal secretions, urine, neutrophils, and macrophages.2 Since alteration in the lysozyme level in human tears has been observed in some ocular diseases,-'2 its measurement can be of considerable diagnostic importance. However, an adequate knowledge of the biological variations is essential for valid comparisons of tear lysozyme levels between healthy and diseased subjects.The present study was undertaken to find out differences, if any, in the tear lysozyme concentration between the two eyes and also the diurnal variation in the same eye. The concentrations of tear lysozyme over a period of time and in relation to age and sex have also been studied. Material and methodsThe study was carried out on healthy Indian subjects belonging to the same racial group. They were either volunteers or had attended the outpatient department of Guru Nanak Eye Centre, New Delhi, for refraction. They had no ocular or systemic disease. All of them had been in the uniform hospital environment for at least two hours prior to sampling.In the first part of the study tear samples were

Variability of tear protein levels in normal young adults: diurnal (daytime) variation

“…This prolonged sampling period may lead to questionable results if the subjects who participated in the study did not have adequate sleep. Sen and Sarin [18], using stimulated tears, also found a significant daytime variation of lysozyme (see Table 1). In their study, lysozyme level was lowest in early morning (6 am), increasing to the highest level at night (10 p.m.).…”

“…A number of investigators have determined the diurnal variations (including daytime changes and both daytime and nighttime changes -see Table 1) of immunoglobulin A (IgA) and lysozyme [7,8,16,18], but with inconsistent results. Huth et al [9] determined the diurnal variation of TPC in four subjects, but the diurnal variation of other major tear proteins, such as lactoferrin and tear-specific prealbumin (TSP), has not been investigated previously.…”

Tear Lacritin Levels by Age, Sex, and Time of Day in Healthy Adults

“…14,36 We also looked at diurnal variation of lacritin over a 24-hour period. In that study, lacritin levels dropped slightly in late afternoon, but the change was minimal, so sampling time from patients would not be crucial for comparison with other tear samples or for lacritin determination.…”

Variability of tear protein levels in normal young adults: between-day variation

“…Major tear proteins, including secretory immunoglobulin A (sIgA), lactoferrin, serum albumin, protein G, tear-specific prealbumin (TSP) and lysozyme, have been consistently separated using the tech-nique of electrophoresis [10,11,17]. Sen and Sarin [18] monitored the level of lysozyme concentration monthly over a period of 1 year and found that the variations were not statistically significant. Little else is known, however, about the day-to-day variation in total tear protein concentration (TPC) and the concentrations of the major tear proteins.…”