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At least 127 records · Page 7Linked to original sources
PubMed2000

Innervation of the cavernous body of the human efferent tear ducts and function in tear outflow mechanism.

The lacrimal sac and nasolacrimal duct are surrounded by a wide cavernous system of veins and arteries comparable to a cavernous body. The present study aimed to demonstrate the ultrastructure of the nervous tissue and the localisation of neuropeptides involved in the innervation of the cavernous body, a topic not previously investigated. Different S-100 protein antisera, neuronal markers (neuron-specific enolase, anti-200 kDa neurofilament), neuropeptides (substance P, neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal polypeptide) and the neuronal enzyme tyrosine hydroxylase were used to demonstrate the distribution pattern of the nervous tissue. The ultrastructure of the innervating nerve fibres was also examined by means of standard transmission electron microscopy. The cavernous body contained specialised arteries and veins known as barrier arteries, capacitance veins, and throttle veins. Perivascularly, the tissue was rich in myelinated and unmyelinated nerve fibres in a plexus-like network. Small seromucous glands found in the region of the fundus of the lacrimal sac were contacted by nerve fibres forming a plexus around their alveoli. Many nerve fibres were positive for S-100 protein (S 100), neuron-specific enolase (NSE), anti-200 kDa neurofilament (RT 97), calcitonin gene-related peptide (CGRP), substance P (SP), tyrosine hydroxylase (TH), and neuropeptide Y (NPY). Vasoactive intestinal polypeptide (VIP) immunoreactivity was only demonstrated adjacent to the seromucous glands. Both the density of nerve fibres as well as the presence of various neuropeptides emphasises the neural control of the cavernous body of the human efferent tear ducts. By means of this innervation, the specialised blood vessels permit regulation of blood flow by opening and closing the lumen of the lacrimal passage as effected by the engorgement and subsidence of the cavernous body, at the same time regulating tear outflow. Related functions such as a role in the occurrence of epiphora related to emotional responses are relevant. Moreover, malfunction in the innervation of the cavernous body may lead to disturbances in the tear outflow cycle, ocular congestion or total occlusion of the lacrimal passages.

Adult↗
PubMed1991

Tear plasminogen activators--indicators of epithelial cell destruction. The effect of scraping, n-heptanol debridement, and alkali burn of the cornea on the plasminogen activator activity of rabbit tears.

Plasminogen activator (uPA) activities were determined in the tears of rabbits following mechanical (scraping) or chemical (n-heptanol) debridement and alkali burn of the central part of the corneal epithelium. All three types of injury enhanced the plasminogen activator activities in the tears. The increase in uPA activity was highest in alkali burn, lowest for n-heptanol debridement. Scraping yielded an intermediate increase in uPA activity. The maximum value in activator activity was reached at 5 hours for mechanical injury and at 24 hours for chemical injuries. uPA activity values returned to the normal range by the time of re-epithelialization for mechanical scraping and 1-3 days following re-epithelialization for heptanol debridement and alkali burn. A trend was observed between uPA activity level and the size of the wound but the correlation was not pronounced (R = 0.538).

Alcohols↗
PubMed1998

Functional anatomy of the human efferent tear ducts: a new theory of tear outflow mechanism.

BACKGROUND: The mechanism of lacrimal drainage under physiological conditions is controversial. The aim of this study was to analyze the three-dimensional architecture of human efferent tear ducts from functional and clinical points of view. A new theory of tear outflow is discussed. METHODS: Thirty-two prepared lacrimal systems of adults were examined by histological, immunohistochemical and scanning electron microscopic techniques. RESULTS: The wall of the lacrimal sac is made up of collagen bundles, elastic and reticular fibers arranged in a helical pattern. Wide luminal vascular plexus are embedded in this helical system and connected to the cavernous tissue of the inferior turbinate in the region of Hasner's valve. Immunohistochemical analysis showed evidence of type I and type III collagen as well as chondroitin 4- and 6-sulfate. CONCLUSION: With blinking, the lacrimal part of the orbicularis muscle contracts. The fornix of the sac moves in a cranial-lateral direction. Thus the lacrimal sac distends and may be "wrung out" due to its medial attachment and helically arranged fibrillar structures. The vascular plexus may play an important role in the absorption and drainage of lacrimal fluid.

Aged↗
PubMed2002

Identification of two highly sialylated human tear-fluid DMBT1 isoforms: the major high-molecular-mass glycoproteins in human tears.

Human open eye tear fluid was separated by low-percentage SDS/PAGE to detect high-molecular-mass protein components. Two bands were found with apparent molecular masses of 330 and 270 kDa respectively. By peptide-mass fingerprinting after tryptic digestion, the proteins were found to be isoforms of the DMBT1 gene product, with over 30% of the predicted protein covered by the tryptic peptides. By using gradient SDS/agarose/polyacrylamide composite gel electrophoresis and staining for glycosylation, it was shown that the two isoforms were the major high-molecular-mass glycoproteins of >200 kDa in human tear fluid. Western blotting showed that the proteins expressed sialyl-Le(a). After the release of oligosaccharides by reductive beta-elimination from protein blotted on to PVDF membrane, it was revealed by liquid chromatography-MS that the O-linked oligosaccharides were comprised mainly of highly sialylated oligosaccharides with up to 16 monosaccharide units. A majority of the oligosaccharides could be described by the formula dHex(0-->2)NeuAc(1-->)(x)Hex(x)HexNAc(x)(-ol), x=1-6, where Hex stands for hexose, dHex for deoxyhexose, HexNAc for N-acetylhexosamine and NeuAc for N-acetylneuraminate. The number of sialic acids in the formula is less than 5. Interpretation of collision-induced fragmentation tandem MS confirmed the presence of sialic acid and suggested the presence of previously undescribed structures carrying the sialyl-Le(a) epitopes. Small amounts of neutral and sulphated species were also present. This is the first time that O-linked oligosaccharides have been detected and described from protein variant of the DMBT1 gene.

Agglutinins↗
PubMed1982

[Studies on the precorneal tear film. First communication: an optical system for demonstrating tear film without fluorescein (author's transl)].

Tear film is usually studied by using fluorescein. An optical system is described which despenses with the use of fluorescein. It mainly consists in an equal diffuse illumination of the cornea, provided through an opaque truncated cone that is illuminated from behind. The cone is situated as close as possible to the front of the eye. The cornea and its surface can be observed through a hole at the narrow end of the cone. Interferences in the lipid layer of the tear film are recognizable as "colors of thin layers". The physical background to interferences in thin, convex layers is discussed. Break-ups are visualized by using a supplementary "Schlieren" method.

Biomechanical Phenomena↗
PubMed1985

Effects of fluorescein on tear breakup time and on tear thinning time.

A simple, noninvasive method of in vivo precorneal tear film stability analysis is described. The method involves observing the first catoptric (first Purkinje) image. The effect of fluorescein on the results and the relation with standard tear breakup time (BUT) are presented.

Adult↗
PubMed1993

Review of the tear break-up time and a closer look at the tear break-up time of Hong Kong Chinese.

The technique of assessing tear stability using the fluorescein instillation technique has been widely used in the clinical diagnosis of "dry eye" and in the screening of potential contact lens wearers. Various inconsistencies in the application of the tear break-up time (TBUT) techniques and the results obtained were noted in the literature and this review summarizes the differences and the conclusions of various investigators. The reliability of this technique using two different methods of observation was examined and the mean TBUT of Hong Kong Chinese subjects (HK-Chinese) was determined. We conclude that the TBUT can be measured reliably using either the scanning or full beam method in most patients. The mean TBUT of HK-Chinese is approximately 8 s and about 70% of HK-Chinese have TBUT's less than 10 s.

Adolescent↗
PubMed1989

Detection of HBs antigen, DNA polymerase activity, and hepatitis B virus DNA in tears: relevance to hepatitis B transmission by tears.

Hepatitis B surface antigen, DNA polymerase, and hepatitis B virus DNA have been sought in the tears of 72 patients. These markers were detected in a high percentage of hepatitis B carriers, which proves the presence of hepatitis B virus in the tears and raises the question of its eventual transmission in this way. The severity and extreme contagiousness of hepatitis B together with the increasing number of virus carriers justify systematic sanitary rules among ophthalmic clinicians and staff, but vaccination remains the best mean of limiting the spread of the disease.

DNA, Viral↗
PubMed1987

[Effect of commercial beta blockers and their combination with artificial tears on the duration of tear film stability].

The influences of 8 different beta-blockers on the tear film stability-measured on the breakup time (BUT) of normal and healthy volunteers-was compared. All beta-blockers led to BUT reduction, however, the lowest influence was observed with levobunolol. The duration of this effect was compared with that of levobunolol, timolol and metipranolol. While the minor BUT alterations induced by levobunolol recovered after 30 min and were completely restored after 1 h, those of the two other beta-blockers lasted for over 2 h. The combination of timolol 0.5% with different artificial tears containing mainly polyvinyl alcohol (PVA) 1.4%, methylcellulose and polyacrylic acid initially led also to BUT reduction. The best results were obtained with PVA 1.4%.

Adrenergic beta-Antagonists↗
PubMed1992

Tear protein G originates from denatured tear specific prealbumin as revealed by two-dimensional electrophoresis.

One-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D-SDS PAGE) of the non-denatured low molecular weight (MW) tear proteins (dilution in phosphate buffered saline or in the non-ionic detergent Triton X100) revealed no protein G but a strongly marked 23-kD related to a tear specific prealbumin (TSP) subunit coming with the known 15, 17, 18 and 20-kD TSP subunits. Under mild denaturating conditions of sample preparation with SDS dilution just before electrophoresis, 23-kD protein decreased and a faint 32-kD protein G appeared. Under stronger denaturing conditions of sample preparation with SDS treatment (boiling or freeze-thaw cycles), 23-kD protein disappeared and two main protein G forms (32 and 34-kD) and additional bands (29, 36, 39, 42, 57 and 60-kD) appeared depending on the sample treatment. The isoelectric pH (pI) of these proteins ranged from pH 5.2 to pH 5.4. Different two-dimensional electrophoresis methods revealed that: - in presence of SDS, 23-kD protein was spontaneously changed into 17-kD TSP and such a phenomenon was partially reversible by using a non-ionic detergent (Triton X100), new proteins appeared under denaturating processes were related to various protein G forms and originated from TSP group, proteins G were produced by the aggregation of TSP subunit related to MW 17-kD/pI 5.0 corresponding to the major TSP subunit, disulfide bond formation was shown to play a major role in the aggregation process although protein G group was not totally reduced by dithiothreitol. Such results suggest that protein G is an in vitro experimental artifact due to denaturing conditions with SDS treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Studies of human tear proteins. 3. Distribution of specific tear prealbumin in lacrimal glands and other ocular adnexa.

Tear fluid is a mixed solution containing many kinds of proteins, and two predominant fractions have been determined by electrophoretic studies. One is anodal specific tear prealbumin (STP) and the other is cathodal lysozyme. This study is the first to demonstrate the localization of STP in the ocular adnexa by the immunofluorescence method. STP was found in the acinar cells of both the main and the accessory lacrimal glands. The cells of the interlobular ducts showed no or only weak staining of STP. No specific staining of STP was found in the conjunctiva, cornea or Meibomian gland. STP as well as lysozyme are thought to be secreted from the main and the accessory lacrimal glands.

Aged↗
PubMed2005

Ultrasound appearance of tendon tears. Part 2: lower extremity and myotendinous tears.

Traumatic tears of the musculotendinous complex at the lower limb are common in clinical practice but can be difficult to detect and to evaluate because of swelling and pain that can limit proper physical examination. They can affect sedentary subjects or active sports participants involved in amateur or professional activities. In the first group tendons are more commonly affected, while myotendinous tears are common in sports players. The aims of this review article are to review the aetiology and pathomechanism of the most common ruptures affecting the tendons and the main myotendinous junctions of the lower extremity and to describe their ultrasound findings as well as to correlate ultrasound appearance with that of the other imaging modalities.

Humans↗
PubMed2001

Assessment of tear concentrations on therapeutic drug monitoring. II. Pharmacokinetic analysis of valproic acid in guinea pig serum, cerebrospinal fluid, and tears.

PURPOSE: To quantitatively describe the pharmacokinetics of valproic acid (VPA) in guinea pig serum (total [Cf+b] and free [Cf]), cerebrospinal fluid (CSF) [C]CSF and tears [C]T using a simple kinetic model, and to examine whether [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. METHODS: [Cf+b], [Cf], [C]CSF and [C]T were determined after bolus i.v. injection of 10 or 20 mg/kg VPA using GC/ECNCI/MS. RESULTS: [Cf+b] could be quantitatively described by a two compartment model with linear elimination kinetics. [Cf] was separately analyzed using multi-exponential equations. [C]CSF was analyzed using a simple kinetic model in which the CSF compartment is independently connected with the serum compartment by the apparent diffusion constants (KINCSF and KOUTCSF). [C]T was analyzed using the same simple kinetic model used for [C]CSF. The values of [C]CSF and [Cf] in the steady state can be represented by the following equations; [C]CSF = KINCSF/KOUTCSF x [Cf], [Cf] = KOUT/KINT x [C]T, and indicating that [Cf] and [C]CSF can be predicted by [C]T using the resulting pharmacokinetic parameters. CONCLUSIONS: The measurement of [C]T which can be collected non-invasively and estimated the pharmacokinetic parameters for [Cf], [C]CSF, and [C]T might be a very useful method for TDM of VPA.

Animals↗
PubMed1981

Tear film physiology and contact lens wear. II. Contact lens-tear film interaction.

The successful fitting of contact lenses requires the practitioner to take into account many properties of the specific lens type used but the practitioner must also understand patient factors including tear properties, use of appropriate solutions, procedures for lens cleaning, and efficiency of blinking. Selection of appropriate patients, selection of lens type, proper fitting, good maintenance, and training and monitoring of patients increase the probability of achieving success.

Conjunctivitis↗
PubMedDate not supplied

[The normal tear fluid and decreased tearing in patients with Sjögren's disease and Sjögren's syndrome. I. The protein and glucose content].

Studies of total proteins, lysozyme and glucose in 25 patients (50 eyes) with Sjogren's disease and 26 patients (52 eyes) with Sjogren's syndrome have revealed a statistically significant reduction of tear production in patients vs. the normal subjects. The results obtained can be used both for diagnostic and therapeutic, purposes, in particular for dry-eye patients.

Female↗
PubMedDate not supplied

[The normal tear fluid and decreased tearing in patients with Sjögren's disease and Sjögren's syndrome. II. The lipid content].

Studies of total lipids--squalene, cholesterol and sterol ethers, fatty acids and their ethers, lanosterol, oxysterols and phospholipids in 25 patients (50 eyes) with Sjogren's disease and 26 patients (52 eyes) with Sjogren's syndrome have revealed a statistically significant reduction of phospholipid quantities and an increase in fatty acids, and cholesterol in patients vs. the normal subjects. Possible influence of lipid components on the structure and function of the tear pellicle is discussed.

Adolescent↗
PubMed2004

Complete, superior labral radial tear and type II slap tear associated with greater tuberosity fracture.

This case report presents a unique variant of superior labral-bicep complex injury. The combination of a complete anterior-superior radial tear of the labrum and bicep anchor instability has not been described in previous classifications of these injuries. The injury was traumatic in nature and was associated with a displaced fracture of the greater tuberosity. The labral pathology was treated by an anatomic repair technique as described. Rationale for the repair performed, as well as implications of the injury treated by debridement alone, are discussed. Clinicians should be aware of different patterns of superior labral-bicep complex injuries and the implications on function and stability of the glenohumeral joint.

Adult↗
PubMed1993

Tear trough implants for correction of tear trough deformity.

This essay describes the tear trough deformity and its extension into the cheek. It is an extremely common and consistently deforming characteristic of the lower orbital region. The article focuses on cause and correction. A suborbital malar implant designed to alleviate the deformity is now available from an implant manufacturer in a variety of sizes. The procedure provides in most instances a definitive correction of a significant disfigurement.

Blepharoptosis↗