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S Pavlovic

Publications and source records attributed to S Pavlovic.

At least 37 records · Page 2Linked to original sources
PubMed2001

Riluzole suppresses post-sigh, but not spontaneous apnoeas during sleep in rats.

We conducted this experiment to determine the role of glutamate in the mechanism of sleep apnoeas by administering riluzole, a glutamate release inhibitor, to freely moving rats in which sleep-related apnoeas are physiological phenomena. Adult Sprague-Dawley rats were implanted with electrodes for electroencephalogram (EEG) and electromyogram (EMG) recording to monitor sleep and were placed inside a single-chamber plethysmograph to monitor respiration. Sleep and respiration were recorded for 6 h following intraperitoneal administration of 0.5, 5.0 and 10.0 mg kg(-1) riluzole. Riluzole dose-dependently suppressed post-sigh apnoeas during rapid eye movement (REM) sleep but had no effect on sleep-related spontaneous apnoeas. The drug (5.0 and 10.0 mg kg(-1)) also dose-dependently reduced wakefulness and increased sleep. It appears that glutamate, an excitatory neurotransmitter, plays a role in the genesis of the post-sigh apnoeas during REM sleep.

Animals↗
PubMed2000

Non-Fc receptor-binding humanized anti-CD3 antibodies induce apoptosis of activated human T cells.

Human trials in organ allografts have demonstrated that murine anti-CD3 mAbs are immunosuppressive. By mimicking Ag, anti-CD3 can produce T cell activation, anergy, or death. Activation of resting T cells in vivo results in dose-limiting cytokine release and is caused by Ab-mediated cross-linking of T cells and Fcgamma receptor (FcR)-bearing cells. With the goal of minimizing cytokine-induced toxicity, anti-CD3 have been engineered to lower Fc binding avidity. Preclinical murine studies have indicated that non-FcR-binding anti-CD3 can induce apoptosis of Ag-activated T cells. Since induction of T cell apoptosis may be an important mechanism of immunosuppression by anti-CD3, we tested whether Fc mutations affect the ability of anti-human CD3 to induce apoptosis of activated T cells. We compared wild-type murine anti-CD3, M291, and OKT3 and their humanized, FcR- and non-FcR-binding structural variants in quantitative assays of T cell apoptosis. Non-FcR-binding variants produced more sustainable phosphorylation of extracellular signal-regulated kinase-2, greater release of IFN-gamma, and more effectively caused activation-dependent T cell apoptosis. Non-FcR-binding variants dissociated more quickly from the T cell surface and caused less internalization of the TCR, which then remained available in greater abundance on the cell surface for signaling. Cross-linking of non-FcR-binding variants by antiglobulin enhanced TCR internalization and minimized induction of T cell apoptosis. We conclude that non-FcR-binding, humanized anti-CD3 have improved ability to induce apoptosis of activated T cells, presumably by allowing durable expression of the TCR and sustained signaling.

Adult↗
PubMed2000

Epilenticular intraocular lens implantation in traumatic cataract with a ruptured posterior capsule.

PURPOSE: To present a case of rapidly progressing traumatic cataract caused by posterior capsule rupture after nonpenetrating ocular injury, as well as a surgical procedure to safely implant the intraocular lens in such a traumatized eye. METHODS: In a 23-year-old man with traumatic cataract and posterior lens capsule rupture, a one-piece polymethylmethacrylate IOL was implanted before cataract extraction into the ciliary sulcus in front of the cataractous lens. Subsequently, the cataract was removed by pars plana lensectomy. RESULTS: The surgery and postoperative course were uneventful. Postoperative visual acuity was 20/20. CONCLUSION: We present a method of intraocular lens implantation in cases of rapidly progressing traumatic cataract caused by posterior capsule rupture after a blunt ocular trauma.

Adult↗
PubMed2000

Silicone intraocular lens implantation in children: preliminary results.

PURPOSE: To evaluate the safety and outcome of foldable silicone intraocular lens (IOL) implantation in children. SETTING: Department of Ophthalmology, University of Giessen, Giessen, Germany. METHODS: The results of cataract extraction and silicone IOL implantation in children having surgery between 1992 and 1997 were retrospectively analyzed in 8 eyes (7 patients). All IOLs were implanted in the capsular bag through a 3.5 mm clear corneal incision. In 4 eyes, primary posterior capsulectomy and anterior vitrectomy were performed. RESULTS: Mean patient age at the time of surgery was 5.1 years (range 8 months to 15 years). The surgeries were uneventful. All IOLs remained anatomically stable and well centered during the mean follow-up of 29.6 months (range 18 to 46 months). Postoperative inflammatory reaction was minimal. Neither fibrinoid exudation nor posterior synechias occurred postoperatively. Postoperative best spectacle-corrected visual acuity ranged from 20/800 to 20/20. All eyes with an intact posterior capsule developed posterior capsule opacification. In the 4 eyes that had primary posterior capsulectomy and anterior vitrectomy, the visual axis remained clear. CONCLUSIONS: These preliminary results suggest that silicone IOL implantation in children is a safe procedure with good and stable short-term anatomic results. Longer follow-up is necessary to answer questions about the long-term safety of silicone lens implantation in a child's eye.

Adolescent↗
PubMed2000

Myotonic dystrophy and cardiac disorders.

Myotonic dystrophy (MD) is a multisystem disease affecting numerous organs and systems. Cardiac involvement is frequent. Sudden death, due to fatal cardiac rhythm and conduction disturbances occurs in 30% of patients with MD. The aim of this study was to assess the possibilities and methods of early detection of myocardial and conduction system disturbances. ECG, 24-hr Holter monitoring, echocardiography and electrophysiologic studies of the conduction system (electrophysiologic study) were carried out in 45 patients. Analysis of late ventricular potentials was done in 36 patients. Genetic studies revealed multiplication of CTG triplets in all patients. Cardiological abnormalities were detected in 89% of our patients. Disturbances of intraventricular conduction with prolongation of HV interval were most frequent (72%). Electrophysiologic study was the most sensitive method for detecting heart involvement in MD (positive findings in 87% patients). Abnormal findings were also discovered by Holter monitoring (64%), ECG (58%), analysis of late ventricular potentials (55%) and by echocardiography in 46% patients. The results of this study indicate a high rate of cardiac involvement in MD.

Adult↗
PubMed2000

Pharmacological radionuclide ventriculography for detection of myocardial contractile reserve in patients after myocardial infarction: head-to-head comparison of low dose dobutamine and low dose dipyridamole.

BACKGROUND: Low dose pharmacological stress echocardiography with either dobutamine or dipyridamole infusion has been proposed for recognition of myocardial viability. However, dependence on adequate acoustic window, observer experience, and the mild degree of wall motion changes make the viability assessment by stress echocardiography especially bothersome. The objective of the study was to evaluate the ability of low dose dobutamine and low dose dipyridamole radionuclide ventriculography to detect contractile reserve in patients after myocardial infarction and functional recovery after coronary angioplasty. METHODS: The study group consisted of 20 consecutive patients (52 +/- 10 years, 17 male, 3 female) with previous myocardial infarction and resting regional dyssynergy, in whom diagnostic cardiac catheterization revealed significant one-vessel coronary artery stenosis suitable for angioplasty. Each patient underwent equilibrium 99m-Tc radionuclide ventriculography which was performed at rest and during low dose dipyridamole (0.28 mg/kg over 2 minutes) and low dose dobutamine infusion (up to 10 mcg/kg/min). Left ventricular global and regional ejection fractions were determined. Increase of regional ejection fraction for > 5% (inferoapical and posterolateral regions) or > 10% (anteroseptal regions) during low dose dobutamine and dipyridamole in infarcted regions, as well as in the followup period, was considered as index of contractile reserve. After 8 weeks of successful angioplasty, resting radionuclide ventriculography was repeated in all patients in order to identify functional recovery of the infarct zone. RESULTS: Out of the 180 analyzed segments (20 x 9), 90 regional ejection fractions have shown depressed contractility. The mean of the regional ejection fractions showing depressed contractility increased from the resting value of 34 +/- 12% to 42 +/- 14% in the follow-up period (p = 0.06). Of the 90 with baseline dyssynergy, 46 were responders during low-dose dobutamine (51%), whereas 32 segments were responders (36%, p = 0.05 vs. dobutamine) during low dose dipyridamole. Positive predictive value of dobutamine and dipyridamole for predicting functional recovery was 72% and 75% (p = ns), respectively. Negative predictive value of dobutamine and dipyridamole was 48% and 69% (p = 0.05), respectively. In the group of patients with most severe dyskinesia (regional ejection fraction < 35%, 42 segments) positive predictive value was 73% and 82%, while negative predictive value was 42% and 64% for low dose dobutamine and low dose dipyridamole respectively (p = ns). CONCLUSION: Although low dose dobutamine induced higher rate of positive responses during radionuclide ventriculography imaging, dipyridamole radionuclide ventriculography has shown superior, particularly negative, prognostic value for predicting functional recovery of infarcted regions.

Journal Article↗
PubMed1999

B cell antigen receptor-mediated activation of cyclin-dependent retinoblastoma protein kinases and inhibition by co-cross-linking with Fc gamma receptors.

Cross-linking the B cell Ag receptor (BCR) to surface Fc receptors for IgG (Fc gamma R) inhibits G1-to-S progression; the mechanism by which this occurs is not completely known. We investigated the regulation of three key cell cycle regulatory components by BCR-Fc gamma R co-cross-linking: G1-cyclins, cyclin-dependent kinases (Cdks), and the retinoblastoma gene product (Rb). Rb functions to suppress G1-to-S progression in mammalian cells. Rb undergoes cell-cycle-dependent phosphorylation, leading to its inactivation and thereby promoting S phase entry. We demonstrate in this paper for the first time that BCR-induced Rb phosphorylation is abrogated by co-cross-linking with Fc gamma R. The activation of Cdk4/6- and Cdk2-dependent Rb protein kinases is concomitantly blocked. Fc gamma R-mediated inhibition of Cdk2 activity results in part from an apparent failure to express Cdk2 protein. By contrast, inhibition of Cdk4/6 activities is not due to suppression of Cdk4/6 or cyclins D2/D3 expression or inhibition of Cdk-activating kinase activity. Cdk4- and Cdk6-immune complexes recovered from B cells following BCR-Fc gamma R co-cross-linking are devoid of coprecipitated D-type cyclins, indicating that inhibition of their Rb protein kinase activities is due in part to the absence of bound D-type cyclin. Thus, BCR-derived activation signals that up-regulate D-type cyclin and Cdk4/6 protein expression remain intact; however, Fc gamma R-mediated signals block cyclin D-Cdk4/6 assembly or stabilization. These results suggest that assembly or stabilization of D-type cyclin holoenzyme complexes 1) is an important step in the activation of Cdk4/6 by BCR signals, and 2) suffice in providing a mechanism to account for inhibition of BCR-stimulated Rb protein phosphorylation by Fc gamma R.

Animals↗
PubMed1999

Early induction of cyclin D2 expression in phorbol ester-responsive B-1 lymphocytes.

B-1 lymphocytes represent a distinct B cell subset with characteristic features that include self-renewing capacity and unusual mitogenic responses. B-1 cells differ from conventional B cells in terms of the consequences of phorbol ester treatment: B-1 cells rapidly enter S phase in response to phorbol ester alone, whereas B-2 cells require a calcium ionophore in addition to phorbol ester to trigger cell cycle progression. To address the mechanism underlying the varied proliferative responses of B-1 and B-2 cells, we evaluated the expression and activity of the G1 cell cycle regulator, cyclin D2, and its associated cyclin-dependent kinases (Cdks). Cyclin D2 expression was upregulated rapidly, within 2-4 h, in phorbol ester-stimulated B-1 cells, in a manner dependent on intact transcription/translation, but was not increased in phorbol ester- stimulated B-2 cells. Phorbol ester-stimulated cyclin D2 expression was accompanied by the formation of cyclin D2-Cdk4, and, to a lesser extent, cyclin D2-Cdk6, complexes; cyclin D2- containing complexes were found to be catalytically functional, in terms of their ability to phosphorylate exogenous Rb in vitro and to specifically phosphorylate endogenous Rb on serine780 in vivo. These results strongly suggest that the rapid induction of cyclin D2 by a normally nonmitogenic phorbol ester stimulus is responsible for B-1 cell progression through G1 phase. The ease and rapidity with which cyclin D2 responds in B-1 cells may contribute to the proliferative features of this subset.

Animals↗
PubMed1999

Combined clear corneal phacoemulsification, vitreoretinal surgery, and intraocular lens implantation.

PURPOSE: To evaluate the technical feasibility, outcome, and incidence of complications after combined clear corneal phacoemulsification with intraocular lens (IOL) implantation and vitreoretinal surgery. SETTING: Department of Ophthalmology, Giessen, Germany. METHODS: The results of combined cataract and vitreoretinal surgery in 38 eyes (36 patients) were retrospectively analyzed. All patients had clinically significant lens opacities and vitreoretinal pathology requiring pars plana vitrectomy. Thirty-seven IOLs were implanted in the capsular bag, and 1 was sulcus fixated. RESULTS: Postoperatively, visual acuity improved in 20 eyes (52.6%), was unchanged in 16 (42.1%), and was worse in 2 (5.3%). Postoperative complications consisted of anterior chamber fibrin exudation (3 eyes), hyphema (2 eyes), vitreous hemorrhage (1 eye), posterior capsule opacification (16 eyes), neovascular glaucoma (2 eyes), proliferative vitreoretinopathy and redetachment (1 eye), and retinal redetachment after silicone oil removal (1 eye). CONCLUSION: Compared with 2 separate operations in patients with significant lens opacities and vitreoretinal pathology, combined cataract and vitreoretinal surgery provided more rapid visual rehabilitation. The visual outcome and complications depended primarily on underlying posterior segment pathology and were not related to the combined procedure technique.

Adult↗
PubMed1999

Primary intraocular lens implantation during pars plana vitrectomy and intraretinal foreign body removal.

PURPOSE: To evaluate visual and surgical outcomes as well as complication rates after cataract extraction and primary intraocular lens (IOL) implantation during pars plana vitrectomy for removal of foreign bodies embedded or impacting in the retina. METHODS: Six consecutive cases of simultaneous cataract extraction and IOL implantation combined with vitreous surgery and intraocular foreign body extraction were retrospectively analyzed. In five cases, the foreign body was intraretinal; in one case, it was preretinal with retinal impact site. The follow-up period ranged from 5 to 45 months (mean 21.3 months). RESULTS: Visual acuity improved by two or more lines in five of six eyes. In five eyes, best-corrected postoperative visual acuity was better than 20/40. One eye was successfully reoperated for retinal detachment that developed 2 months postoperatively. In four eyes, the IOL was implanted into the capsular bag; in two cases, the IOL was placed in the ciliary sulcus. No postoperative complication was attributed to IOL implantation. CONCLUSION: Primary IOL implantation after combined cataract and vitreoretinal surgery is a safe and attractive option, reducing the need for two separate operations in selected patients with penetrating ocular injury and retained intraocular foreign bodies. The main advantage is more rapid visual rehabilitation with a single operation, reducing costs and patient discomfort.

Adult↗
PubMed1998

[Early posterior capsule fibrosis after combined cataract and vitreoretinal surgery with intraocular air/SF6 gas tamponade].

BACKGROUND: The surgical approach in treating coexisting vitreoretinal disease and cataract is controversial. We report on patients who developed early posterior capsular fibrosis after combined cataract and vitreoretinal surgery with air/SF6-gas tamponade. PATIENTS AND METHODS: The medical records of 15 consecutive eyes (13 patients) who underwent combined phacoemulsification with intraocular lens implantation and vitreoretinal surgery with intraocular air/SF6-gas tamponade were retrospectively analyzed. The indications for vitreous surgery included: subfoveal neovascular membrane in age-related macular degeneration (5 eyes), macular hole (4 eyes), macular pucker (2 eyes), rhegmatogenous retinal detachment (2 eyes), persistent vitreous haemorrhage after branch retinal vein occlusion (1 eye), persistent vitreous haemorrhage and/or tractional retinal detachment in proliferative diabetic retinopathy (1 eye). The mean follow-up period was 7 months (1-13 months). A control group consisted of 15 eyes (15 patients) who underwent the equal combined operation without intraocular tamponade. The indications for vitreous surgery were persistent vitreous haemorrhage in proliferative diabetic retinopathy (5 eyes), persistent vitreous haemorrhage after branch retinal vein occlusion (5 eyes), asteroid hyalosis (2 eyes), macular pucker (1 eye), posttraumatic vitreous haemorrhage (1 eye), acute retinal necrosis (1 eye). The mean follow-up was 8 months (2-13 months). The posterior capsule was examined at the slit lamp microscopy with maximal dilated pupils. We defined posterior capsular opacification (PCO) as severe if posterior capsule was fibrotic, diffusely thickened and opaque. Modest PCO was characterized by focal fibrotic opacifications at otherwise clear posterior capsule. RESULTS: Severe posterior capsular fibrosis developed in 9 eyes (60%) after 2-14 weeks postoperatively (mean 8 weeks) including 3 of 6 eyes with air tamponade (50%) and 6 of 9 eyes with 20% SF6-gas tamponade (66.7%). In 6 eyes (40%) Nd:YAG-laser capsulotomy was performed 4-14 weeks postoperatively (mean 8.5 weeks). In the control group modest PCO developed in 8 eyes (53.3%) 1-13 months postoperatively (mean 6.5 months) none requiring Nd:YAG-laser capsulotomy during follow-up period. CONCLUSIONS: Combined cataract and vitreoretinal surgery with intraocular air/SF6-gas tamponade induces severe posterior capsular fibrosis in the early postoperative period. The capsular fibrosis is presumably caused by accumulation of fibrin and proliferation stimulating factors in the narrow space between intraocular lens and air/SF6-gas bubble.

Aged↗
PubMed1998

Management of intra-ocular foreign bodies impacting or embedded in the retina.

PURPOSE: To identify both the clinical features of eyes suffering penetrating ocular injury with intra-ocular foreign bodies (FB) impacting or embedded in the retina and the results of surgical outcome and complication rates. METHODS: Thirty-eight consecutive cases of penetrating ocular injuries with intra-ocular FB impacting or embedded in the retina were retrospectively analysed. RESULTS: The FB were metallic in 30 eyes (78.9%; 19 ferromagnetic) and were non-metallic in eight eyes (21.1%). Magnetic extraction was performed in 17 cases (44.7%) and instrumental extraction was performed in 21 cases (55.3%). In two cases, pars plana vitrectomy and FB removal was combined with penetrating keratoplasty, temporary keratoprosthesis and anterior segment reconstruction because of severe explosive injury to the eye. At the final postoperative examination, 32 eyes (84.2%) had completely attached retinas. Visual acuity (VA) improved postoperatively in 18 eyes (47.4%). A final VA of 0.5 or better was achieved in nine of 23 eyes (39.1%) with FB in the peripheral retina and in one of 15 eyes (6.7%) with posterior pole and/or optic nerve head involvement. There was no difference in the final VA regarding the time elapsed between trauma and the removal of the FB. CONCLUSION: The late anatomical and functional outcome in eyes with penetrating ocular injury and FB impacting or embedded in the retina is mostly uncertain, despite immediate and complex surgery. Final anatomical and functional outcome in the present study was influenced by location and extent of the initial damage to the posterior pole. The time that had elapsed between trauma and removal of the FB did not influence final visual function.

Adolescent↗
PubMed1997

[Endophthalmitis after intra-oral block of the infraorbital nerve].

BACKGROUND: Most penetrating needle puncture injuries occur in retro- or peribulbar anesthesia. Hereby only a small percentage of patients develop endophthalmitis. Ocular penetration after enoral infraorbital nerve block has not yet been reported in literature. HISTORY AND FINDINGS: In June 1995 a 74-year-old man presented with a fulminant fibrinous and purulent endophthalmitis. Because he suffers from trigeminal neuralgia his anesthesiologist performed an infraorbital nerve block from enoral two days ago. During this procedure the patient felt a sharp ocular pain. THERAPY AND OUTCOME: We suspected an ocular penetration and performed a vitrectomy with intravitreal antibiotic instillation on the admission-day. A needle penetration site near the inferior rectus muscle was detected and after exocryocoagulation a 5 mm wide radial buckle was sutured over penetration site. Three months postoperatively vision recovered from hand moving to 20/50 and all infiltrations had been disappeared. Only preexisting cataract prevented a better vision. 10 months later after successful cataract extraction with intraocular lens implantation patient left hospital with a vision of 20/30. CONCLUSION: Careful anamnesis would have prevented this accidental globe penetration. Right upper palate is absent presumably due to congenital cleft malformation or surgery. This allowed needle penetration through smooth tissue into the right globe. Fortunately, endophthalmitis develops only in a small percentage after needle puncture. We recommend immediate pars-plana-vitrectomy and intravitreal antibiotics in case of endophthalmitis after ocular penetration.

Aged↗
PubMed1997

[Interaction of silicone oil with various intraocular lenses. A light and scanning electron microscopy study].

BACKGROUND: Silicone oil is increasingly used as an intravitreal tamponade in severe forms of vitreoretinal disorders, also in pseudophakic eyes. In some patients silicone oil was observed to be adherent to the intraocular implant. MATERIAL AND METHODS: To investigate the interaction of silicone oil with IOL-materials and the influence of lipoproteins of the serum on this interaction we used the following in vitro experimental set-up: Sterile IOLs of different IOL-materials (e.g. PMMA, silicone, hydrogel) and surface-modifications (e.g. Pharmacia 809P and 809C, Soflex LI41U, Alcon AcrySof M60BM, Allergan SI-30NB, SI-40NB, Chiron adatomed 90D, C10 and C31UB, MemoryLens U940A, Corneal ISHEMA 66, Storz H60M) were stored in vitro together with silicone oil (1000 centistokes) with and without a fresh serum solution at 37 degrees Celsius. This combination was rotated slowly and mixed thoroughly three times a day. After 3 and 6 months and a standardized special preparation in an ultrasound bath and air treatment, the IOLs were examined by light microscopy followed by scanning electron microscopy. RESULTS: Silicone oil strongly adhered to holes and to the IOL surface especially in silicone and PMMA IOLs. Highly hydrophylic IOLs-like the heparin-surface-modified and hydrogel IOL-cleared from silicone oil relatively early. This effect was more pronounced in the group with lipid-/serum solution than without. In some silicone IOLs silicone oil was strongly adherent to the lens and it was nearly impossible to wash off the oil even when using an alcoholic solution. One silicone IOL lost its haptics in the serum-oil-IOL-mixture, another lost small particles from the IOL surface. CONCLUSION: Silicone oil is more adherent to hydrophobic IOLs than to hydrophylic IOLs. Lipoproteins of the serum play an important role in facilitating an effect of silicone oil on IOL materials. We recommend highly hydrophylic especially surface-modified IOLs for lens implantation following vitreoretinal silicone oil surgery. Implantation of silicone IOLs in vitreoretinal high risk eyes should be avoided.

Equipment Failure Analysis↗
PubMed1997

Effect of head position on refraction in aphakic and phakic silicone-filled eyes.

BACKGROUND: The refraction of the eye is altered significantly after the instillation of silicone oil into the vitreous cavity because of the silicone oil's high refractive index. The degree of the refractive change shows diurnal variation and depends on the patient's head position. PATIENTS AND METHODS: To analyze the degree and time course of refractive changes with respect to head position, the authors performed objective refraction in five aphakic and five phakic silicone oil-instilled eyes with attached maculae using an automatic hand-held refractometer. In each patient, 25 measurements were taken at short intervals using a hand-held autorefractometer with the patient in different positions (supine, head tilted down, and primary eye position). RESULTS: The highest shift of refraction was +5.95 +/- 2.63 diopters spherical equivalent in aphakic eyes and +2.45 +/- 0.71 diopters in the phakic eyes after the patient's position was changed from supine to head tilted down. Three minutes after the position change the refractive shift was stable in almost all eyes. Only slight changes in cylinder and the respective corresponding axis with a mean cylinder shift of 10.1 +/- 5.1 degrees were noted. CONCLUSIONS: Immediately after the head position was changed, aphakic eyes demonstrated more pronounced refractive shifts than phakic eyes. The results of this study explain patients' reports of diurnal changes in visual acuity after intraocular silicone oil instillation. Refractive changes caused by silicone oil stabilized a few minutes after a change in head position.

Aphakia, Postcataract↗
PubMed1996

Influence of physical exercise and nifedipine on ocular pulse amplitude.

BACKGROUND: Ocular pulse amplitude (OPA) was measured to investigate the influence of peripheral vasoconstriction and vasodilation on choroidal perfusion in healthy volunteers and to determine whether low OPA in low-tension glaucoma (LTG) patients is associated with a vasospastic reaction and its response to the calcium channel blocker nifedipine. METHODS: OPA was determined using the Langham ocular blood flow (OBF) system, applanation intraocular pressure (IOP), systemic blood pressure, and heart rate were measured, and ocular perfusion pressure was calculated before and after exercise and smoking in 12 otherwise nonsmoking, healthy volunteers and prior to and for 3 months after initiation of nifedipine therapy in 32 LTG patients with and without a vasospastic reaction as manifested by a nailfold capillary blood flow test. RESULTS: Exercise significantly (P < 0.05) increased heart rate, systolic blood pressure and ocular perfusion pressure, while it significantly (P < 0.05) reduced IOP and diastolic blood pressure. However, OPA was not significantly (P > 0.1) affected by changes in these parameters. Smoking significantly (P < 0.05) increased systolic and diastolic blood pressure, heart rate, and ocular perfusion pressure but did not significantly (P > 0.09) alter OPA. There were two distinct LTG subtypes, with and without a vasospastic reaction. Only those with a vasospastic reaction showed a significant (P < 0.001) increase in OPA after 3 months of nifedipine treatment, while all other parameters tested were not significantly altered. CONCLUSION: Despite affecting ocular and systemic perfusion parameters, exercise and smoking did not alter OPA, suggesting functional isolation, i.e. autoregulation of the choroidal and/or ophthalmic artery circulation in healthy volunteers. Low OPA in LTG was increased by nifedipine only in vasospastic LTG patients, suggesting different, vasotonus-related pathologies. Calcium channel blockers and other vasodilators may be useful in vasoreactive LTG patients with reduced OPA.

Adult↗