PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Intraocular fluid”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1986

Verapamil and diarrhoea in the carcinoid syndrome--clinical and experimental observations on serotonin release.

A patient with the midgut carcinoid syndrome with severe diarrhoea and proven hypersecretion of serotonin (5-HT) was treated with low doses of verapamil perorally. During treatment the patient was completely relieved of diarrhoea but discrete facial flushing persisted during treatment. When treatment was cessated, diarrhoeas recurred. This patient underwent pentagastrin (PG) provocation repeatedly; during untreated conditions injection of PG released 5-HT, detectable in peripheral venous blood. Such release was abolished during verapamil treatment, but recurred after withdrawal of the drug. Surgical biopsies from this tumour were studied in two experimental models: cell suspensions and heterotransplants grown in the anterior eye-chamber of immunosuppressed rats. Release of 5-HT from the cell suspensions was elicited in a dose-dependent manner after stimulation with isoprenaline (IP) suggesting activation of beta-adrenoceptors on the tumour cells. Such release was reduced after pretreatment with verapamil indicating a calcium dependent mechanism. Intraocular tumour transplants also responded with release of 5-HT into the chamber fluid after conjunctival application of IP. However, pretreatment of the rats with verapamil significantly reduced the IP-stimulated release of 5-HT.

Aged↗
PubMedDate not supplied

The balloon-gas procedure: a technique for repair of retinal detachments requiring large volumes of gas.

This report describes the balloon-gas procedure, a technique for obtaining large volumes of intraocular gas. With the balloon-gas procedure a kind of "external fluid-gas exchange" allows for the safe injection of up to 1.0 ml of gas without previous pars plana vitrectomy or surgical drainage of subretinal fluid. From April 1985 to October 1988, in Tübingen, this procedure was utilized in 36 retinal detachments with breaks not suited for scleral buckling: giant tears (nine eyes), large dialyses (seven eyes), posterior breaks (16 eyes), and multiple breaks at different latitudes (four eyes). Follow-up ranged from six to 28 months (average 16 months). Initial retinal reattachment was achieved in 28 eyes (77.8%). Reasons for initial failure were proliferative vitreoretinopathy in six eyes, and a missed break in two. Redetachment occurred in three eyes. All 11 failures were reoperated using segmental sponges (eight eyes) and gas injection (three eyes). Final reattachment was achieved in 29 of the 36 eyes (80.6%), and final failure was due to proliferative vitreoretinopathy in all seven detachments.

Adolescent↗
PubMed1981

The effect of haemodilution on arterial blood pressure, central venous pressure, intracranial and intra-ocular pressures in pigs.

During the open-heart surgery, haemodilution is performed before extracorporeal circulation is started by the sampling of autologous blood and substituting an electrolyte solution. Following extracorporeal circulation, first the machine-blood and then the autologous blood is reinfused. The haemodilution and reinfusion procedures lead to alterations in blood osmolality and tissue fluid distribution, initiating changes in arterial blood pressure, central venous pressure, intracranial and intraocular pressures. These changes were studied in pigs. It is believed that these potentially hazardous pressure alterations can be minimized through proper handling of the procedure. This study presents some of the mechanisms involved.

Animals↗
PubMed1999

A case of an intraocular foreign body due to graphite pencil lead complicated by endophthalmitis.

We report a case of an 8-year-old boy who presented with an intraocular foreign body composed of graphite pencil lead. The patient had been accidentally poked in the right eye with a graphite pencil. Primary care consisted of corneal suturing and lens extraction. Two pieces of the pencil lead remained in the vitreous cavity following surgery, and 2 days later the patient developed endophthalmitis. Pars plana vitrectomy was performed immediately and the intraocular foreign bodies were removed through the scleral wound. Cultures of the vitreous fluid revealed no bacterial organisms. X-ray fluoroscopic analysis of the vitreous detected 1 ppm of aluminum (a constituent of the pencil lead). Although the clinical presentation indicated probable bacterial endophthalmitis, the detection of elemental aluminum within the vitreous cavity also suggested the possibility of further retinal toxicity due to some dissolving of the pencil lead.

Cataract↗
PubMed1989

[Increase in aqueous flare by a therapeutic dose of mannitol in humans].

To evaluate the effects of mannitol on aqueous flare (aqueous protein concentration), we administered an intravenous clinical therapeutic dose to normal young adults (average age, 20.1 years), to normal older adults (average age, 61.3 years), and also to patients with diabetes mellitus, systemic hypertension, or pseudoexfoliation syndrome who were about to undergo intraocular surgery (average age, 66.4 years). Protein and cell levels in the aqueous fluid were determined with a device that measures laser light scattering in the aqueous fluid. Mannitol increased aqueous flare intensity. In all subjects, aqueous flare intensity was greatest around one hour following drug administration; the magnitude and the duration of the aqueous flare increase were significantly greater in normal older subject than in normal young adults; the magnitude was essentially the same in older adults with and without diseased barrier. The effect was reversed within 6 hours of drug administration in normal subjects. We considered the findings to represent changes in actual aqueous protein concentration and discussed the possible causes of this phenomenon.

Adult↗
PubMed1999

Pathogenesis of gram-positive bacterial endophthalmitis.

The severity of endophthalmitis has been associated generally with the virulence of the offending pathogen. However, precisely what constitutes the virulence in intraocular infections remains ill defined. We therefore sought to identify the basis for virulence for three common ocular pathogens (Bacillus cereus, Enterococcus faecalis, and Staphylococcus aureus) in terms of intraocular growth rates, bacterial localization patterns, and the contribution of cell walls and secreted products to the pathogenesis of endophthalmitis. Rabbit eyes were injected intravitreally with (i) viable B. cereus, E. faecalis, or S. aureus, (ii) metabolically inactive B. cereus, E. faecalis, or S. aureus, (iii) sacculus preparations from each strain, or (iv) culture fluid containing products secreted by each strain. Eyes were assessed at various times following injection by slit lamp biomicroscopy, electroretinography (ERG), bacterial and inflammatory cell enumeration, and histology. B. cereus endophthalmitis followed a more rapid and virulent course than E. faecalis or S. aureus endophthalmitis, eliminating retinal responsiveness, as measured by ERG, by 12 h. Analysis of bacterial localization revealed that B. cereus uniquely migrated rapidly from posterior to anterior segment during infection. Although injection of neither metabolically inactive bacteria nor cell wall sacculi greatly affected ERG, significant intraocular inflammation was observed. Injection of B. cereus or S. aureus culture fluids caused both significant reductions in retinal responsiveness and significant intraocular inflammation, paralleling that seen in natural infections. The results demonstrate that toxins, intraocular localization, and, to a lesser extent, the intraocular host response to cell walls all contribute to the pathogenesis of B. cereus, S. aureus, and E. faecalis endophthalmitis in a pathogen-specific manner. The key pathophysiologic differences in these intraocular diseases highlight opportunities for optimizing conventional therapies and deriving new ones.

Animals↗
PubMedDate not supplied

Twenty-gauge Transconjunctival Vitrectomy.

PURPOSE: To describe a new 20-gauge transconjunctival vitrectomy procedure that we designed, to evaluate its usefulness, and to compare two different methods of use. METHODS: The records of 431 patients (433 eyes) who underwent 20-gauge transconjunctival vitrectomy at the Surugadai Hospital of Nihon University between March 2003 and January 2004 were studied retrospectively. In surgical method 1, 20-gauge wounds were made through the conjunctiva and sclera together. In surgical method 2, 20-gauge conjunctival openings were made 2 mm posterior to the sclerotomies. Absorbable sutures were used to stitch the scleral and conjunctival openings simultaneously in both methods. RESULTS: A 20-gauge transconjunctival vitrectomy has various benefits and is indicated for nearly all ocular diseases. Moreover, it is not limited by the intraocular instruments required. However, since cannulas were not placed in all ports, conjunctival edema occurred more easily with surgical method 2 owing to the leakage of perfusion fluid. CONCLUSIONS: This new 20-gauge transconjunctival vitrectomy procedure has various benefits and is indicated for nearly all ocular diseases. It is not limited by the intraocular instruments required.

Adult↗
PubMed2003

Pseudo-hypopyon as the presenting feature in B-cell and T-cell intraocular lymphoma.

The clinicopathologic correlation of two patients with primary intraocular lymphoma is described, both of whom had a rare and unusual presentation of hypopyon uveitis. Sampling of aqueous fluid proved the cytopathologic diagnosis of B-cell lymphoma in the first patient. In the second patient an iris biopsy confirmed a T-cell lymphoma. The samples were examined using haematoxylin and eosin, and immunohistochemical stains. These patients were diagnosed with primary intraocular lymphoma on initial presentation with hypopyon uveitis. Secondary glaucoma was noted in the patient with T-cell lymphoma. Both cases appeared confined to the eye and initially responded favourably to aggressive chemotherapy and radiotherapy, but later went on to develop systemic involvement. Clinicians should be aware of this dramatic mode of presentation, which is unusual for ocular lymphoma.

Adult↗
PubMed1990

High-speed photography of Er: YAG laser ablation in fluid. Implication for laser vitreous surgery.

The mechanism of Er:YAG laser-induced long-range damage in intraocular surgery was investigated using high-speed photography. A short pulse of 2.94-microns radiation delivered by an optical fiber into an aqueous medium causes rapid localized heating and vaporization and creates a bubble at the tip of the fiber. The size of the bubble depends on the pulse energy and is about 1 mm at 1 mJ. The shape of the bubble has multiple lobes, which can be attributed to the spiky output of the laser pulse. The expanding bubble can cause thermal and mechanical damage to tissues. In addition, laser spikes propagating through the bubble can strike and damage tissue on the distal side of the bubble. In both mechanisms the damage zone approximates the bubble size and can be greater than 1 mm, ie, 1000 times the steady-state absorption length of water at 2.94 microns. The authors discuss ways to reduce the damage zone by bubble confinement.

Hot Temperature↗
PubMed1993

[Pressure-induced change in corneal curvature in patients with refractive surgery and unoperated probands].

Helmholtz suspected there was a connection between intraocuclar pressure and lateration of corneal curvature. With a view to potential changes in corneal stability following different refractive procedures, we tried to demonstrate these side effects by increasing the intraocular pressure. A tilting-table was used to induce a rapid pressure increase via the fluid shift. Corneal curvature was measured by photokeratoscopy before and after pressure changes. The results were different in corneas subjected to radial and photorefractive keratotomy than in intact corneas. We suggest a physical model that might provide an explanation.

Adolescent↗
PubMed1985

Expansion of long-acting gas bubbles for intraocular use. Principles and practice.

Expansion of long-acting gas bubbles used in vitreoretinal surgery may lead to increased intraocular pressure and central retinal artery occlusion. To further understand the principles controlling the expansion of long-acting gases, we compared the expansion of perfluoropropane gas bubbles with that of sulfur hexafluoride gas bubbles in an in vitro model, as well as in rabbits. We found that perfluoropropane bubbles expand more rapidly and to a greater extent than do sulfur hexafluoride bubbles in the first 24 hours. The early rate of expansion of a long-acting gas is largely dependent on convection of the surrounding fluid and is independent of the type of long-acting gas. Early postoperative monitoring of intraocular pressure is, therefore, equally important when using any long-acting gas.

Animals↗
PubMedDate not supplied

[Ultrasonic cyclodialysis in glaucoma surgery in aphakia].

The authors present the results of a new method for surgical treatment of aphakic eye glaucoma with the use of low-frequency ultrasound. The suggested surgery, ultrasonic cyclodialysis, was carried out in 15 patients with glaucoma on the aphakic eyes. A follow-up of 6 months has demonstrated a stable normalization of intraocular pressure. The mechanism of the hypotensive effect of the operation is explained largely by improvement of fluid discharge and a certain inhibition of the chamber humor production. The authors emphasize the sparing nature of the operation and a serene postoperative course.

Anterior Chamber↗
PubMed1982

The effect of salt loading diet on the intraocular pressure.

Salt tablets are habitually ingested by some people while doing physical exercise in hot climate, in order to prevent sodium depletion. The effects of supplementary salt on the intraocular pressure was investigated on 5 healthy acclimatized subjects who rode a bicycle ergometer at temperature of 35 degrees C and relative humidity of 40%. A significant decrease of 1.0 mmHg in their mean intraocular pressure was detected when 10.2 gm NaCl was added daily to the normal diet. The pressure reduction was associated with changes of the body fluid balance.

Adult↗
PubMed1993

Complement activation by polymethyl methacrylate minimized by end-point heparin attachment.

After intraocular lens implantation, despite good clinical results, many cataract patients develop a chronic uveitis, caused by an inflammatory response to the implant. One way to improve the biocompatibility of the intraocular lens is to modify the surface by end-point heparin attachment. This study shows that complement activation caused by poly(methyl methacrylate) can be diminished by end-point heparin attachment, as demonstrated by a significant reduction in the generation of C3a and fluid phase terminal complement complexes. It suggests that assessment of complement activation is a good indicator of the biocompatibility of intraocular lenses.

Biocompatible Materials↗
PubMed1993

Echographic evaluation of glaucoma shunts.

BACKGROUND: It is frequently impossible to determine by clinical examination alone if a filtering bleb is present over the equatorial plate(s) of a glaucoma shunt. This uncertainty can result in management dilemmas when patients with these devices have elevated intraocular pressures (IOPs). The authors describe how standardized echography can be used to determine if fluid is present around the plates and to characterize the blebs. METHODS: Four hundred twenty-seven plates in 269 patients who had undergone single- or double-plate Molteno implantation underwent standardized echography (both A- and B-scan examinations) to determine if blebs were present around the plates, primarily when results of slit-lamp examinations had been inconclusive. Bleb sizes, locations, and characteristics also were evaluated. RESULTS: Sixty-five percent of the plates had associated blebs, which were graded according to their sizes (small, medium, and large, in 29%, 44%, and 27% of plates with blebs, respectively). Fluid (which appeared as an echolucent area) could be seen underlying and/or overlying the plates (which appeared as echodense lines). Larger blebs were often associated with scleral flattening. Although bleb sizes did not necessarily correlate with the levels of IOP control, the presence of a bleb on ultrasound was indicative of tube patency. CONCLUSION: Standardized echography was invaluable in the postoperative management of patients who had undergone Molteno implantation because it demonstrated the presence or absence of blebs and characterized them when results of slit-lamp examinations had been inconclusive. This technique also can be used to evaluate similarly designed aqueous shunting devices.

Adult↗
PubMed2000

Absence of herpesvirus DNA by polymerase chain reaction in ocular fluids obtained from immunocompetent patients.

OBJECTIVE: To assess the prevalence of herpesvirus DNA in ocular fluids obtained from healthy patients undergoing vitreoretinal surgery. BACKGROUND: Polymerase chain reaction (PCR) has been used to detect herpesvirus DNA in patients with acute retinal necrosis and cytomegalovirus retinitis. Little is known regarding the prevalence of detectable herpesvirus DNA in ocular fluids collected from healthy seropositive patients with no clinical evidence of viral retinitis. METHODS: Seventy-five intraocular specimens (35 aqueous and 40 vitreous samples) were collected from 75 patients undergoing scleral buckling or vitrectomy. Using a PCR-based assay, the authors tested each specimen for the presence of herpesvirus genome DNA with primers specific for cytomegalovirus, Epstein-Barr virus, herpes simplex virus types 1 and 2, and varicella zoster virus. Serologic testing for immunoglobulin G (IgG) and IgM levels corresponding to each of the herpesviruses was also performed. RESULTS: Of the 75 samples tested, none was found to harbor herpesvirus DNA. The assay did not give false-positive results in patients with active intraocular inflammation. The sensitivity of the assay was 0.08 infection-forming units for cytomegalovirus, 0.6 tissue culture infectious doses for herpes simplex virus, 0.5 infected-cell equivalents for Epstein-Barr virus, and 0.03 focus-forming units for varicella zoster virus. The percentage of patients with positive herpesvirus serology ranged from 86% to 100% and was consistent with rates observed in the general population. CONCLUSIONS: The prevalence of herpesvirus DNA detectable by PCR techniques in ocular fluids appears to be quite low despite the high proportion of patients who tested positive for herpesvirus antibodies. Therefore, a positive result obtained in a patient presenting with vitreoretinal inflammation should be regarded as significant.

Adolescent↗