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At least 37 records · Page 2Linked to original sources
PubMed2006

Repeated measurements of dynamic tear distribution on the ocular surface after instillation of artificial tears.

PURPOSE: To determine the repeatability of real-time optical coherence tomography (OCT) measurements of tear film thickness (TFT) and variables of tear film menisci. METHODS: Forty eyes were imaged with a custom-built, real-time OCT to obtain heights, curvatures, and cross-sectional areas of upper and lower tear menisci simultaneously. The central TFT was indirectly determined as the difference between the combined thickness of the central cornea and tear film and the true corneal thickness obtained after instillation of artificial tears. Dynamic tear distribution was determined by OCT imaging immediately and 5, 20, 40, and 60 minutes after tear instillation. Measurements taken after two blinks of one eye at each visit were repeated on the next day. Measurements from the companion eye were made on separate days. RESULTS: There were no significant differences between the two measurements of each variable made on consecutive days. At baseline, upper tear meniscus variables were strongly correlated with the comparable lower meniscus variables. However, there were no significant correlations between TFT and any tear meniscus variable. Immediately after instillation of artificial tears, all measured variables increased significantly. TFT, upper and lower menisci heights, and upper meniscus area remained elevated for at least 5 minutes. In addition there were significant correlations between TFT and the lower tear meniscus height and area. CONCLUSIONS: The custom-built OCT showed good repeatability and holds promise in measuring the dynamic distribution of artificial tears on the ocular surface.

Adult↗
PubMed1982

Studies of human tear proteins--1. Analysis of tears from normal subjects by crossed immunoelectrophoresis.

Tears were collected from 10 normal subjects by two methods, 1) micropipetting after stimulation with an onion slice, and 2) Schirmer 1 test using a filter paper strip. The tears in the 5 x 5 mm part of the filter paper placed within the conjunctival sac were extracted with a 0.9% NaCl solution. The tear samples so obtained were analyzed by crossed immunoelectrophoresis. Nineteen proteins were identified by the use of monospecific antisera. Ten tear-specific proteins including the specific tear prealbumin of Bonavida et al., lactoferrin and lysozyme were identified by the intermediate gel method. Some differences were found in the pattern of the tear-specific proteins between the tears collected by the two methods, but the pattern was basically similar. Some individual differences were also found. The levels of serum proteins including albumin and IgG varied considerably, but it was thought to be due to dilution by reflex lacrimation during tear sampling. On the other hand, the pattern of the tear-specific proteins was fairly constant. The filter paper method allowed tear protein analysis, even in patients with 0 mm wetting by the Schirmer 1 test. A study of the length-volume relationship of the filter paper wetting showed that the tears contained in the 5 x 5 mm portion of the filter paper were about 1.8 microliters. The filter paper method was thought to offer a reliable clinical tool for the study of the tear proteins in various pathological conditions of the lacrimal secretion.

Adult↗
PubMedDate not supplied

Incomplete tears of the subscapularis tendon associated with tears of the supraspinatus tendon: cadaveric and clinical studies.

This study was undertaken to evaluate incomplete tears of the subscapularis tendon that occur in conjunction with small or medium-sized tears of the supraspinatus tendon. Fifty-two shoulders were examined in 26 embalmed cadavers. The average age at the time of death was 76.3 years. Rotator cuff tears were observed in 32 (61.5%) shoulders. Six (11.5%) shoulders had massive rotator cuff tears and were excluded from the study, leaving 46 shoulders for study. Twenty shoulders had a tear of the supraspinatus tendon, and 17 had a tear of the subscapularis tendon. All tears of the subscapularis tendon were articular-side incomplete tears. On histologic examination most pathologic changes of the subscapularis tendon were observed on the articular side of the upper portion. Lesions of the long head of the biceps brachii were identified in 14 (30.4%) shoulders. A statistically significant correlation was found between tears of the subscapularis tendon and the presence of lesions of the long head of the biceps brachii (P=.0014). In addition, the results of preoperative magnetic resonance imaging of 15 patients (average age, 62.9 years) with a surgically confirmed diagnosis of incomplete tears of the subscapularis tendon in conjunction with tears of the supraspinatus tendon were also evaluated. Incomplete tears of the subscapularis tendon could be identified on magnetic resonance imaging as an area of high signal intensity on axial T2-weighted images in all 15 shoulders studied.

Aged↗
PubMed2002

Evaluation of tear film interference patterns and measures of tear break-up time.

PURPOSE: The purpose of this study was to compare the agreement within and between examiners when evaluating real-time and digital photographs of TearScope Plus tear film interference patterns. We also evaluated between-examiner agreement of noninvasive digital tear break-up time (NITBUT) using the TearScope, the relation between NITBUT and tear film interference patterns, and the relation between NITBUT and tear break-up time (TBUT). METHODS: Forty nondry eye patients were seen for digital imaging of the tear film using the TearScope Plus mounted on a slit-lamp with the EyeCap Ophthalmic Image Capture System. Two independent examiners first assessed the tear interference pattern in real-time and then captured the patterns and NITBUT digitally for a period of approximately 60 s. Each image series was later graded for interference pattern and NITBUT by the two independent, masked examiners. RESULTS: Within-examiner comparisons of real-time and digital tear pattern photograph grading showed moderate to substantial agreement for experienced examiners (kappa for examiner 1 = 0.76 and kappa for examiner 2 = 0.55). Between-examiner agreement when grading tear patterns was also substantial in real-time (kappa = 0.72) and moderate when using digital photography (kappa = 0.59). The between-examiner mean NITBUT was 11.2+/-6.8 s and the 95% limits of agreement between examiners were -19.2 to +9.2 s. The mean TBUT was 7.6+/-10.4 s, and it was on average 3.7+/-12.0 s shorter than NITBUT (p = 0.06). Thicker tear film interference patterns graded photographically were associated with longer NITBUTs for both examiners (p = 0.001). CONCLUSIONS: There is moderate to substantial within- and between-examiner agreement when comparing real-time and digital tear interference patterns photographs when using the TearScope. Although there is considerable between-examiner variability with the NITBUT test, the thicker lipid layer tear patterns tend to be associated with longer NITBUTs.

Adult↗
PubMed2005

Surface pressure measurements of human tears and individual tear film components indicate that proteins are major contributors to the surface pressure.

PURPOSE: Tear film stability has been associated with a low surface tension (high surface pressure), which has been attributed to a variety of tear film components. In this study, we examined the contribution of various tear proteins, mucin, and meibomian lipids to the surface pressure of human tears. METHODS: A Langmuir trough was used to measure and compare the surface activities of albumin, lipocalin, beta-lactoglobulin, lactoferrin, lysozyme, secretory IgA, mucin, meibomian lipid, and tears. RESULTS: All proteins exhibited surface activity. The surface pressure-area (Pi-A) profiles of most protein films at equilibrium surface pressure (Pieq) were sigmoidal and showed hysteresis between the expansion and compression phases of the cycle. Pieq of most proteins took 4-9 hours to occur. By contrast, the Pi-A profiles for meibomian lipid films were hyperbolic rather than sigmoidal and had little hysteresis, and Pieq was attained within 1 hour. The Pi-A profiles of mucin films showed mostly hyperbolic characteristics with small hysteresis. The Pi-A profiles of films of tears were sigmoidal, showed strong hysteresis, and reached Pieq at about 5 hours. Partitioning of the proteins and whole tears into the subphase also occurred. CONCLUSION: Comparison between the dynamic Pi-A profiles of tears and those of individual tear film components shows that tear film proteins not only are capable of surface activity but also are major contributors to the surface activity of the tear film.

Albumins↗
PubMed2006

Relationships between central tear film thickness and tear menisci of the upper and lower eyelids.

PURPOSE: To investigate the relationship between central tear film thickness (TFT) and tear menisci of the upper and lower eyelids using real-time optical coherence tomography (OCT). METHODS: Both eyes of healthy subjects were imaged with a real-time OCT to obtain height, curvature, and area of upper and lower tear menisci simultaneously. Central TFT was indirectly measured by calculating the difference between baseline measurements of the central corneal thickness plus tear film and the true corneal thickness obtained after instillation of artificial tears. Results from two normal blinks were obtained from one eye at each visit and repeated the next day. RESULTS: The average central TFT was 3.4 +/- 2.6 microm. The upper tear meniscus curvature, height, and area were 239 +/- 112 microm, 268 +/- 68 microm, and 22,732 +/- 11,974 microm2 respectively. There were no significant differences in curvatures, heights, or areas between upper and lower tear menisci, nor were there any differences in measured variables between the two blinks at each visit or between the two repeated visits in the right and left eye groups (P > 0.05). The upper and lower tear menisci in each eye group on each day correlated strongly with curvature, height, and area (all P < or = 0.03). However, no tear meniscus variable was a significant predictor of TFT (all P > 0.44). CONCLUSIONS: OCT is a promising tool in the measurements of TFT and dimensional variables of tear menisci. Upper and lower tear menisci have nearly identical dimensions.

Adult↗
PubMed1985

Studies of human tear proteins: 4. Analysis by crossed immunoelectrophoresis of tears in various diseases.

Tears were collected from patients with familial amyloidotic polyneuropathy (FAP), orbital tumors, sarcoidosis, trigeminal and facial nerve palsy and corneal ulcer. These tears were analyzed by crossed immunoelectrophoresis. Two cases of FAP with deficiency of lacrimation and keratoconjunctivitis sicca showed normal tear protein patterns. In these cases, the deficiency of lacrimation may have been due chiefly to disturbance of the peripheral parasympathetic nerve innervating the lacrimal gland. Five other patients with FAP showed from slight to severe decrease in the tear-specific proteins. One of two cases with lacrimal gland tumor showed a decrease in the tear-specific proteins before removal of the tumor. After the surgery two patients showed significant decrease or disappearance of the tear-specific proteins. Three cases with other orbital tumors revealed no alterations in production of tear proteins. The case of sarcoidosis with keratoconjunctivitis sicca showed a decrease in the tear-specific proteins. Lacrimal gland involvement in sarcoidosis was confirmed by the tear protein analysis. The patient with facial and trigeminal nerve palsy showed a decrease in the tear-specific proteins. This was thought to be due to atrophy of the main lacrimal gland caused by functional disturbance of the lacrimal nerve. The analysis of tear proteins is useful in the diagnosis of lacrimal gland tumor disturbing the gland function and also of other diseases involving the lacrimal gland.

Adult↗
PubMedDate not supplied

Magnetic resonance diagnosis of meniscal tears in patients with acute anterior cruciate ligament tears.

OBJECTIVE: To evaluate the accuracy of magnetic resonance imaging in the diagnosis of meniscal tear in patients with acute anterior cruciate ligament tears. METHODS: Magnetic resonance images obtained from 41 patients imaged within 6 weeks of injury who had acute anterior cruciate ligament tears identified at arthroscopy were retrospectively reviewed for meniscal tear. RESULTS: With MR imaging the sensitivity, specificity and accuracy for diagnosing meniscal tears in the presence of acute anterior cruciate ligament tears were 71%, 93%, and 88%; for the lateral meniscal tears were 57%, 100% and 85%; and for the medial meniscal tears were 100%, 88%, 90%. All false negative cases (n = 6) involved the posterior horn of the lateral meniscus. CONCLUSION: In the presence of acute anterior cruciate ligament tears, MRI imaging has relatively low sensitivity for detecting meniscal tears due to missed tears in the lateral meniscus.

Acute Disease↗
PubMed1998

Menopause and tear function: the influence of prolactin and sex hormones on human tear production.

PURPOSE: The onset of dry eye is very common during menopause and may result from the loss of hormonal support. The purpose of this study was to assess the effect that changes in sex hormone and prolactin levels have on tear function in premenopausal and menopausal woman. METHODS: Women between the ages of 30 and 60 were solicited to participate in a study concerning menopause and tear function. One-hundred and ten women were given tear function tests (osmolarity, tear volume, tear flow, Schirmer's test) and serum levels were measured for total testosterone, estradiol, prolactin, and follicle stimulating hormone. RESULTS: For all women on hormone replacement therapy, we found a strong negative correlation between serum prolactin level and tear function. For women in menopause, total testosterone correlated positively with tear function, whereas for premenopausal women there was a negative correlation between total testosterone and tear function. Serum estradiol levels correlated positively with tear function for women 30-39 years of age, whereas for menopausal women the correlation was negative. CONCLUSIONS: This is the first demonstration in humans that tear production is correlated with serum prolactin and sex hormone levels prior to and during the menopause.

Adult↗
PubMed2006

Tear breakup dynamics: a technique for quantifying tear film instability.

PURPOSE: The purpose of this study was to develop a novel, quantitative measurement of tear film breakup dynamics (TBUD) to study the phenomenon of tear breakup in dry eye and control subjects and its impact on dry eye symptoms. METHODS: Ten control and 10 dry eye subjects completed the Dry Eye (DEQ) and other questionnaires. After the instillation of sodium fluorescein, subjects kept the tested eye open for as long as possible, similar to a staring contest, while tear film breakup was videotaped (S-TBUD). The maximum blink interval (MBI) and tear breakup time (TBUT) were measured from digital movies by a masked observer. Individual frames of movies were converted to gray-scale images, maps of relative tear film fluorescence were generated, and the total area of tear breakup (AB) of the exposed cornea was quantified. RESULTS: On average, dry eye subjects demonstrated a higher AB and shorter TBUT and MBI, but only the AB was significantly different (p = 0.023). Subjects most often used the descriptors stinging and burning to describe their sensations during staring trials. The AB showed a high correlation between eyes and with some DEQ symptom measures. CONCLUSIONS: These methods allow objective quantification and tracking of the phenomenon of tear breakup. Our results suggest that tear breakup stresses the corneal surface, resulting in stimulation of underlying nociceptors. The tear film of dry eye subjects was less stable than controls. They had a larger AB measured from the last video frame before MBI (i.e., just before blinking) than did controls. This perhaps reflects adaptation to the repeated stress of tear instability in dry eye.

Adult↗
PubMed1997

Comparative study of tear substitutes and their immediate effect on the precorneal tear film.

Dry eye patients present with instability of the precorneal tear film which breaks up much earlier than normally. The instability of the precorneal tear film leads to dry eye symptoms such as the sensation of sand in the eye, recurrent blurred vision, itching, smartness, and the sensation of dryness. The stability of the precorneal tear film can be evaluated by the break-up-time test (BUT). The aim of treatment of dry eye is to increase the precorneal tear film stability. Tear substitutes are the most frequent medication for dry eye patients, who request life-long treatment. Therefore, we estimated the influence of tear substitutes on the precorneal tear film stability. The influence of unpreserved artificial tear substitute containing 0.1% sodium hyaluronate (Healon 0.1%) was compared with that of 7 different available tear substitute preparations containing preservatives. The results of the present study show that Healon 0.1% has the best influence on the precorneal tear film stability. These data were found to be independent of the viscosity property of Healon 0.1%.

Adolescent↗
PubMedDate not supplied

Natural history of asymptomatic rotator cuff tears: a longitudinal analysis of asymptomatic tears detected sonographically.

The purpose of this study was to examine longitudinally the natural history of asymptomatic rotator cuff tears over a 5-year period and to assess the risk for development of symptoms and tear progression. Since 1985 through the present, bilateral sonograms were done on all patients. A review of consecutive sonograms done from 1989 to 1994 revealed 58 potential patients with unilateral symptoms who had contralateral asymptomatic rotator cuff tears. Of these 58 patients, 45 (22 men, 23 women) responded to a comprehensive questionnaire and 23 additionally returned for examination and repeat sonographic evaluation. The questionnaire was based on the American Shoulder and Elbow Surgeons score and included several outcome-based questions. A physical examination was performed in a standardized fashion along American Shoulder and Elbow Surgeons guidelines. Repeat high-resolution sonograms were performed by a single experienced radiologist. Primary and repeat sonograms were then reassessed for tear size and location by two independent experienced radiologists blinded to the clinical data results. Twenty-three (51%) of the previously asymptomatic patients became symptomatic over a mean of 2.8 years. The average Activities of Daily Living score for those remaining asymptomatic was 28.5 of 30 and for those becoming newly symptomatic, 22.9 of 30 (P <.5). The mean visual analog pain score (1 = no pain) for those remaining asymptomatic was 1.1 and for the newly symptomatic patients, 4.0. Of the 23 patients who returned for ultrasound, 9 were asymptomatic and 14 symptomatic. Only 2 of the 9 patients remaining asymptomatic had progression of their tears. Overall, 9 of 23 patients had tear progression. No patient had a decrease in the size of the tear. Our results demonstrate that symptoms can develop in patients with previously asymptomatic rotator cuff tears when seen in the context of a contralateral symptomatic tear. Development of symptoms was associated with a significant increase in pain and decrease in the ability to perform activities of daily living (P <.05). There appears to be a risk for tear size progression over time.

Activities of Daily Living↗
PubMedDate not supplied

Medial and lateral meniscal tear patterns in anterior cruciate ligament-deficient knees. A prospective analysis of 575 tears.

We used our database to evaluate the locations of meniscal tears associated with anterior cruciate ligament injuries. Five hundred seventy-five meniscal tears were seen in 476 patients. Each tear was categorized prospectively according to the side (medial/lateral), the radial zone of the tear, and the circumferential zone of the tear. The different tear locations were then compared for the medial and lateral menisci and evaluated for statistical significance. We found a nearly equal number of tears on the medial (305) and lateral (270) sides. A significantly greater number of tears on the medial side as compared with the lateral side were posterior (99.4% versus 87.8%) and peripheral (75.4% versus 44.1%). Peripheral posterior horn tears of the medial meniscus were the most common type of tear (230 of 575, 40%) by a statistically significant amount.

Adolescent↗
PubMed1999

Corneal surface regularity and the effect of artificial tears in aqueous tear deficiency.

PURPOSE: To evaluate corneal surface regularity and the effect of artificial tears on the regularity of the corneal surface in dry eye. DESIGN: A prospective, clinic-based, case-control study. PARTICIPANTS: A total of 64 eyes of 33 normal subjects and 42 eyes of 22 patients with aqueous tear deficiency were evaluated. METHODS: Indices of the TMS-1 corneal topography instrument (Tomey Technology, Cambridge, MA) were used to evaluate corneal surface regularity and potential visual acuity (PVA) in patients with aqueous tear deficiency dry eye before and after the instillation of artificial tears and in normal subjects. The TMS-1 topographic maps were classified into round, oval, symmetric bow-tie, asymmetric bow-tie, and irregular patterns. MAIN OUTCOME MEASURES: The surface regularity index (SRI), surface asymmetry index (SAI), PVA index, and topographic pattern of the TMS-1 were compared between normal and dry eyes and in dry eyes before and after the instillation of artificial tears. RESULTS: The SRI and SAI were significantly elevated and the PVA was significantly reduced in dry eye patients compared with normal subjects: 0.31+/-0.22, 0.30+/-0.16, and 20/17.89+/-20/3.04, respectively, in normal subjects and 1.28+/-0.73, 1.05+/-1.17, and 20/33.45+/-20/13.99, respectively, in patients with dry eye (P<0.001 for all indices). The average amount of astigmatism was also increased in dry eyes (2.10+/-1.96 prism diopters) compared with normal eyes (1.13+/-0.53 prism diopters, P = 0.02). In dry eyes, the SRI and SAI were positively correlated with corneal fluorescein staining scores (P = 0.005 for SRI and P = 0.016 for SAI). The mean PVA was not significantly different from the mean actual corrected visual acuity. The dry eyes had a significantly lower percentage of symmetric bow-tie patterns and a greater percentage of irregular patterns on topographic maps than normal eyes. After the instillation of artificial tears, the SRI, SAI, and mean astigmatism all decreased significantly (P<0.001 for SRI, P<0.002 for SAI, P = 0.04 for astigmatism) and the PVA improved (P<0.001) in dry eyes. An irregular topographic pattern was observed in 45.24% of dry eyes, and this decreased to 30.95% after the instillation of artificial tears (P<0.005). CONCLUSIONS: Patients with aqueous deficiency have an irregular corneal surface that may contribute to their visual difficulties. The SRI and SAI could be used as objective diagnostic indices for dry eye as well as for evaluating the severity of this disease and the effect of artificial tears. Artificial tears have the secondary benefit of smoothing the corneal surface in dry eye.

Aged↗
PubMedDate not supplied

Measurement of pH, electrolytes and electrophoretic studies of tear proteins in tears of patients with dacryoliths: a novel concept for dacryoliths.

Dacryolithiasis is one of the causes of acquired nasolacrimal duct obstruction, although its origin is unclear. The purpose of this study was to investigate the differences in tear constituents between patients with nasolacrimal duct obstruction with dacryoliths and those without dacryoliths. In a prospective case-control study, undiluted tears were collected from 30 eyes from 30 patients with partial acquired nasolacrimal duct obstruction (PANDO) consisting of 17 PANDO patients with dacryoliths and 13 PANDO patients without dacryoliths. The pH, and the Na(+), K(+), Cl(-), total calcium and total protein concentrations were determined. The composition of the tear proteins was assessed by cellulose acetate electrophoresis. In the tear samples from 17 eyes with PANDO/dacryoliths, the mean +/- SD K(+) level was 15.6 +/- 3.1 mEq/l. In the tear samples from 13 PANDO controls, the mean +/- SD K(+) level was 19.8 +/- 4.9 mEq/l. The difference between the two groups was statistically significant (p = 0.02). In the tear samples from PANDO/dacryolith patients, the mean +/- SD total protein level was 129.0 +/- 72.9 mg/dl. In the tear samples from the PANDO controls the mean +/- SD total protein level was 261.6 +/- 132.5 mg/dl. The difference between the two groups was statistically significant (p = 0.00). In the tear protein fractions from electrophoresis, a low level of lysozyme was observed in the PANDO/dacryolith samples compared with the PANDO control samples (p = 0.03). The tears from patients with PANDO due to dacryoliths showed a change in the concentrations of electrolytes and protein, particularly lysozyme, compared with that of the patients with PANDO without dacryoliths, which may be related to the pathogenesis of dacryoliths.

Adult↗
PubMedDate not supplied

Electrolytes and electrophoretic studies of tear proteins in tears of patients with nasolacrimal duct obstruction.

This study was performed to determine whether there are differences in tear constituents between normal persons and patients with primary acquired nasolacrimal duct obstruction (PANDO) and to correlate differences in tear composition with the degree of PANDO. We tested 30 normal persons (mean age 42.0 +/- 21.4 years) and 34 PANDO patients (mean age 44.8 +/- 17.9 years) consisting of 18 cases with complete obstruction and 16 cases with partial obstruction. We measured the pH, the concentration of Na(+), K(+), Cl(-), total calcium and total protein of the tears. The composition of tear protein was assessed by cellulose acetate electrophoresis. The data were analyzed by a t test. The pH was more alkaline in patients with PANDO (7.11 +/- 0.38), especially in cases with complete obstruction (7.14 +/- 0.30, p = 0.47) compared with the normal persons (6.94 +/- 0.35). The concentration of Na(+), K(+), Cl(-) and total protein were similar in normal and PANDO cases, while total calcium concentration was significantly higher in PANDO (2.62 +/- 1.70 mg/dl) compared with the normal cases (1.73 +/- 0.97 mg/dl), (p = 0.015). This change was found in both cases with complete obstruction (2.47 +/- 1.25 mg/dl, p = 0.027) and cases with partial obstruction (3.00 +/- 2.16 mg/dl, p = 0.009). PANDO patients had lower levels of tear protein fraction (TPF) 1 (p = 0.006) and higher levels of tear TPF 4 (p = 0.000) than normal persons. Tears in PANDO cases were more alkaline, higher in calcium concentration, and unstable in the proportion of tear proteins compared with normal persons. These results may improve our understanding of tear physiology and the pathogenesis of PANDO.

Adult↗
PubMed1989

Gel electrophoresis of human tears reveals various forms of tear lactoferrin.

Lactoferrin is a metal binding protein, which is present in high concentrations in human tears. Little is known concerning the exact molecular shape of lactoferrin in tears. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting experiments showed that this protein is present in multiple forms in tear fluid. SDS-PAGE analysis of human tears under non reducing conditions and pretreatment of tears in sample buffer at room temperature revealed lactoferrin in a major form of 60 kD, a minor form of 64 kD and a third form of 52 kD. Pretreatment of tears at elevated temperatures prior to sample application resulted in the loss of this third form. Disruption of intrachain disulfide bridges prior to SDS-PAGE analysis resulted in a shift in the apparent molecular weight of lactoferrin to 78 kD and 83 kD for the major and minor form, respectively. Chromatography of human tears on ConA-Sepharose as well as enzymatic deglycosylation showed that the difference in molecular weight of the major and minor lactoferrin form was not due to a variation in the carbohydrate side chains. The presence of the minor form could also not be ascribed to iron saturation. Instead we found that addition of iron ions to human tears resulted in a shift of tear lactoferrin to a lower molecular weight species of about 52 kD, coinciding with the third lactoferrin form mentioned above and a small protein band of approximately 57 kD, representing the iron saturated minor lactoferrin form. Similar findings were observed using purified milk lactoferrin. Increasing the temperature prior to sample application or disruption of disulfide bridges dissociated the iron-lactoferrin complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Epidermal growth factor in human tear fluid: increased release but decreased concentrations during reflex tearing.

To further clarify the role of epidermal growth factor (EGF) in the physiology and pathophysiology of the ocular surface the effects of reflex tearing on concentrations of EGF in tear fluid were studied. Tear fluid samples were collected with glass capillaries before (basal samples, 59 eyes, 30 individuals) and during reflex tearing (stimulated samples, n = 212, 40 eyes, 20 individuals). The rate of tear fluid flow in the capillaries (TFFc) was measured. The concentrations of human EGF (hEGF) was determined by time-resolved immunofluorometric assay (TR-IFMA). The first basal samples contained higher concentrations of hEGF than the samples from the contralateral eyes (n = 28) collected thereafter (p less than 0.05). The basal samples from 40 eyes contained a significantly higher mean concentration of hEGF (8466 pg/ml) than did the stimulated samples (n = 212, 2763 pg/ml); p less than 0.001). The mean TFFc increased from 63 nl/s to 506 nl/s during reflex tearing (p less than 0.001) and the amount of hEGF released from 567 fg/s (n = 40) to 1400 fg/s (n = 212; p less than 0.001). Basal samples from females contained higher concentrations of hEGF than did those from males. The maintenance of the hEGF concentration at a certain level and the increased amount of hEGF released into the tear fluid during reflex tearing suggests continuous release of hEGF into tear fluid from the lacrimal gland.

Epidermal Growth Factor↗