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Biomedical subjects

M Uram

Publications and source records attributed to M Uram.

At least 19 recordsLinked to original sources
PubMed1996

Endoscopic fluorescein angiography of the ciliary body in glaucoma management.

BACKGROUND AND OBJECTIVE: The laser endoscopy system has been modified to permit high resolution intraoperative fluorescein angiograms. Because the ciliary processes can be directly viewed and photocoagulated from a limbal wound in the phakic, aphakic, or pseudophakic eye in virtually any patient, the novel opportunity to angiographically study the ciliary processes before and after various forms of ablation was created. PATIENTS AND METHODS: Eighty patients were divided into four groups and were studied under various conditions. RESULTS: The ciliary processes normally fill with fluorescein early in the angiogram and maintain hyperfluorescence throughout. Functional ciliary processes (or portions of them) are hyperfluorescent; ablated processes are densely hypofluorescent. This technique can delineate inadequately treated zones, permitting appropriate correction at the time of initial surgery. Eyes with previous transscleral cyclodestruction did not experience the degree of ciliary process ablation that the surgeon reported. CONCLUSION: Intraoperative delineation of treated and untreated ciliary processes permits accurate correlation with observed intraocular pressure response.

Ciliary Body↗
PubMed1996

Endoscopic fluorescein angiography.

BACKGROUND AND OBJECTIVE: To assess features of various retinal and choroidal disorders by endoscopic fluorescein angiograms (EFAs) obtained intraoperatively. PATIENTS AND METHODS: One hundred patients undergoing vitrectomy were studied intraoperatively by injecting 5 ml of 10% fluorescein intravenously. Up to 110 degrees field of view high-resolution angiograms were obtained endoscopically. Characteristics of diabetic retinopathy, retinal vein occlusion, retinal vasculitis, exudative macular degeneration, and neovascular glaucoma were recorded. RESULTS: Capillary nonperfusion, retinal vascular occlusion or incompetence, and neovascularization of the disc, retina, subretinal space, and posterior iris could be delineated. CONCLUSION: EFA defines pathologic retinal/choroidal areas intraoperatively, which may permit more selective surgical management during vitrectomy.

Choroid Diseases↗
PubMed1995

A lack of supersensitivity to opioid receptor agonists following chronic spinal opioid receptor antagonist administration in the rat.

1. Male Sprague-Dawley rats were chronically tested with intrathecal (i.t.) receptor selective opioid antagonists to determine if antinociceptive supersensitivity developed to selective i.t. opioid receptor agonists. 2. A subcutaneously implanted osmotic minipump was used to deliver the mu-opioid receptor antagonist CTOP (0.3 nmol) or the delta-opioid receptor antagonist naltrindole (5.5 nmol) for 7 days. 3. Following a 24 hr washout period, rats received a single i.t. dose (ED50) of either DAMPGO (for CTOP-treated animals) or DPDPE (for naltrindole-treated animals) and the antinociceptive effects of the agents were tested on the tail-flick test. 4. Our findings revealed that chronic spinal treatment with selective opioid receptor antagonists did not induce an antinociceptive supersensitivity to selective opioid receptor agonists. 5. Perhaps this lack of supersensitivity is reflective of difficulties inherent to opioid receptor antagonists that do not possess negative intrinsic activity.

Animals↗
PubMed1995

Endoscopic cyclophotocoagulation in glaucoma management.

Laser endoscopy is an exciting development that affords ophthalmologists new opportunities in the management of retinal disease, oculoplastics, and glaucoma. This report elucidates the technology and its application in the treatment of glaucoma, as well as highlighting the differences between conventional glaucoma therapy and endoscopic laser management.

Anterior Chamber↗
PubMed1994

Age-related changes in the spinal antinociceptive effects of DAGO, DPDPE and beta-endorphin in the rat.

These studies were designed to investigate how the aging process alters the spinal antinociceptive efficacy of mu (mu), delta (delta) and epsilon (epsilon) opioid receptor agonists administered intrathecally (i.t.) in rats. Various doses of the mu agonist DAGO, the delta agonist DPDPE or the putative epsilon beta-endorphin were injected i.t. in young (5-6-month-old), mature (15-16-month-old) and aged (25-26-month-old) Fischer 344 rats. Antinociception was measured using the rat tail-flick analgesiometric assay. The data demonstrated a decline in spinal opioid-induced antinociception as a function of age. For instance, the i.t. dose of DPDPE or beta-endorphin needed to produce antinociception in the 25-26-month-old rats was higher than that needed to elevate tail-flick latency in the young and mature animals. We also noted that the i.t. doses of the opioid agonists needed to produce 'antinociception' in the aged cohort were within a range of spinal doses that produced motor impairment. Apparently, the aging process alters the ability of opioid receptors to mediate antinociception. Perhaps an age-related decrease in the number and/or affinity of opioid receptor sites in the rat spinal cord accounts for these observations.

Aging↗
PubMed1994

Laser endoscope in the management of proliferative vitreoretinopathy.

PURPOSE: To evaluate the ability of the ophthalmic laser microendoscope for improving the outcome of vitrectomy in the management of grade D3 anterior proliferative vitreoretinopathy. METHODS: Ten consecutive patients without diabetes who had grade D3 anterior proliferative vitreoretinopathy underwent vitrectomy, lensectomy, membranectomy, gas-fluid exchange, and endophotocoagulation. Endoscopically guided portions of the vitrectomy and endophotocoagulation process were assessed, particularly in the region of the pars plana, ciliary body, posterior iris, and internal aspect of sclerotomy sites. RESULTS: Follow-up ranged from 3 months to 1 year (mean, 9.2 months). Six of ten patients maintained total reattachment of the retina throughout the follow-up period. The retinas of the remaining patients redetached. Visual acuity for patients with reattached retinas ranged from 20/80 to hand motions. CONCLUSION: Because endoscopy enhances the ability of the surgeon to image and dissect gliotic membranes in the regions of the pars plana, ciliary body, and posterior iris, as well as allow complete photocoagulation, a higher probability of anatomic success seems possible.

Endoscopes↗
PubMed1992

The noradrenergic component contributing to spinal fentanyl-induced antinociception is supraspinally mediated.

1. Male Sprague-Dawley rats were fitted with intrathecal (i.t.) and intracerebroventricular (i.c.v.) catheters. Fentanyl was injected either i.t. or i.c.v., and the antinociceptive efficacy of fentanyl was evaluated using the tail-flick analgesiometric assay. 2. Fentanyl dose-dependently elevated tail-flick latency (TFL) following i.c.v. or i.t. administration. The antinociceptive effects of fentanyl were reversed by naltrexone. 3. Experiments were also designed to evaluate the effects of serotonin and alpha-adrenoceptor antagonists on i.t. or i.c.v. fentanyl-induced elevations in TFL. 4. Phentolamine administered i.t. reversed both the spinal and supraspinal antinociceptive effects of fentanyl, whereas i.t. methysergide did not significantly alter the i.t. or i.c.v. effects of the mu agonist. 5. These data suggest that fentanyl-induced antinociception does not rely on local serotonergic neuronal activation. Due to the highly lipophilic nature of fentanyl, it is possible that the noradrenergic component contributing to spinal fentanyl-induced analgesia is supraspinally-mediated.

Adrenergic Antagonists↗
PubMed1992

Ophthalmic laser microendoscope endophotocoagulation.

PURPOSE: The purpose of this article is to describe the function of the ophthalmic laser microendoscope as it pertains to endophotocoagulation in the management of vitreoretinal disease. METHODS: Fifty-four consecutive vitrectomies with endophotocoagulation were performed using the ophthalmic laser microendoscope instead of endoillumination and endophotocoagulation probes. Intraoperative and postoperative efficacy and complications were evaluated. RESULTS: The ophthalmic laser microendoscope was used to illuminate and view the retina and to deliver diode laser energy in the management of posterior retinal breaks, proliferative retinopathies, and proliferative vitreoretinopathy. The technique of endophotocoagulation was similar to that used routinely in vitreoretinal surgery. The photocoagulation lesions that were created were identical to those delivered by standard endophotocoagulation probes. Intraoperative complications were few, consisting of transient mild retinal or choroidal hemorrhages. Severe postoperative complications related to endophotocoagulation or to use of the ophthalmic laser microendoscope were not observed. CONCLUSION: The ophthalmic laser microendoscope appears to be a safe and effective method of delivering diode laser energy to the retina while simultaneously providing illumination, video recording, and a clear endoscopic view despite anterior segment conditions that might otherwise preclude adequate visualization and treatment. Fewer instrument insertions/removals were required for endophotocoagulation. Post-treatment search for peripheral iatrogenic retinal breaks was accomplished by endoscopy.

Endoscopy↗
PubMed1992

Ophthalmic laser microendoscope ciliary process ablation in the management of neovascular glaucoma.

PURPOSE: To evaluate the potential efficacy of ophthalmic laser microendoscope photocoagulation of the ciliary processes in the management of intractable neovascular glaucoma. METHODS: Ten patients with intractable neovascular glaucoma underwent ophthalmic laser microendoscope ciliary process ablation via a pars plana incision. The device and surgical technique are discussed. RESULTS: Preoperative intraocular pressure (IOP) ranged from 36 mmHg to 62 mmHg (mean, 43.6 mmHg). Postoperative final IOP ranged from 3 mmHg to 27 mmHg (mean, 15.3 mmHg). This represents an absolute decrease of 28.3 mmHg (65%). Postoperatively, 9 eyes had an IOP of less than 21 mmHg, although 3 of these eyes required medication. One eye attained a final IOP of 27 mmHg. All eyes were treated once. Nine patients were treated with carbonic anhydrase inhibitors preoperatively, and six patients were able to discontinue this medication postoperatively. Phthisis was not observed, but hypotony evolved in two eyes with chronic retinal detachment. Follow-up ranged from 6 to 11 months (mean, 8.8 months). CONCLUSION: This new therapeutic modality, which combines endoscopic visualization of the ciliary processes with diode laser photocoagulation, can be effective in the management of intractable neovascular glaucoma.

Adult↗
PubMed1991

Serotonin contributes to the spinal antinociceptive effects of morphine.

This study was designed to determine if morphine administered intrathecally (IT) interacts with serotonergic or noradrenergic nerve terminals in the spinal cord to produce analgesia on the spinally mediated tail-flick test. Male Sprague-Dawley rats were fitted with IT catheters. One week later, animals were spinally pretreated with receptor antagonists selective for opioid, serotonin or alpha-adrenoceptors, and the ability of these agents to alter spinal morphine-induced antinociception was assessed. Morphine dose-dependently elevated tail-flick latency in a naltrexone-reversible manner. The serotonin receptor antagonists spiroxatrine (5-HT1A), pindolol (5-HT1B), ritanserin (5-HT2) and ICS 205-930 (5-HT3) attenuated the spinal analgesic effects of morphine. In contrast, the alpha 1 and alpha 2-adrenoceptor antagonists prazosin and yohimbine, respectively, did not alter morphine-induced elevations in tail-flick latency. These data substantiate earlier reports that spinal morphine-induced antinociception relies on an opioid receptor-mediated component in addition to a local serotonergic component. The finding that the alpha-adrenoceptor antagonists did not alter the antinociceptive effects of IT morphine suggests that spinal norepinephrine does not contribute to the analgesic effects of the opiate.

Adrenergic Antagonists↗
PubMed1991

Analgesic effects of serotonin and receptor-selective serotonin agonists in the rat spinal cord.

1. Serotonin (5-HT) and selective 5-HT receptor agonists were administered intrathecally (i.t.) in rats, and the antinociceptive efficacy of these agents was assessed on the tail-flick and hot plate tests. 2. The 5-HT receptor agonists examined in this study included the 5-HT1A agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT), the 5-HT1B agonist m-trifluoromethylphenylpiperazine (TFMPP), the 5-HT2 agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and the 5-HT3 agonist phenylbiguanide (PBG). 3. None of these agents produced significant elevations in tail-flick latency (TFL) at doses which produced elevations in hot plate latency (HPL). 4. In contrast, the i.t. dose of 5-HT which elevated TFL also produced analgesia on the hot plate test. 5. Serotonin-induced elevations in TFL were reversed by pindolol, ritanserin and ICS 205-930, suggesting that 5-HT interacts with more than one 5-HT site in the spinal cord to produce analgesia on the tail-flick test. 6. The finding that ritanserin reversed 5-HT-induced elevations in HPL suggests that the 5-HT2 site is primarily responsible for mediating the spinal antinociceptive effects of 5-HT on the hot plate test.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1989

Spinal beta-endorphin analgesia involves an interaction with local monoaminergic systems.

beta-Endorphin administered intrathecally (i.t.) in rats produced a dose-dependent elevation in tail-flick latency. Naltrexone administered i.t. as a pretreatment reversed the spinal antinociceptive action of beta-endorphin, suggesting that the opioid interacts directly with spinal opiate receptors. Spinal administration of the alpha 1-adrenoceptor antagonist WB-4101 failed to alter the analgesic effects of the opioid, whereas the alpha 2-adrenoceptor antagonist yohimbine completely blocked beta-endorphin-induced elevations in tail-flick latency. Thus, there is an apparent specificity for the alpha 2-adrenoceptor to mediate the spinal action of beta-endorphin. The 5-HT1 and 5-HT3 receptor antagonists (spiroxatrine and ICS 205-930, respectively) also reversed the analgesic effects of the opioid, while the 5-HT2 receptor antagonist ritanserin only partially blocked beta-endorphin-induced elevations in tail-flick latency. The present results suggest that beta-endorphin produces analgesia at the spinal level via an opiate receptor-mediated interaction with spinal monoaminergic nerve terminals.

Adrenergic alpha-Antagonists↗
PubMed1989

Branch retinal-artery obstruction: a review of 201 eyes.

A study of 187 patients (201 eyes) with branch retinal-artery occlusion (BRAO) was done to determine the etiology, natural history, and treatment of this disorder. On follow-up, almost 90% of the patients had visual acuity of 20/40 or better. The rest had poor visual acuities initially. The patient population was divided into three groups according to treatment. Group I included 65 patients treated aggressively with mechanical and pharmaceutic measures to reduce intraocular pressure and with anti-platelet drugs. Group II was composed of 81 patients treated only with antiplatelet agents given chronically. Group III (41 patients) received no treatment and represented the control group. No statistically significant difference in visual outcome was found on comparison of these three groups of patients. In this study we observed that 98% of the BRAO cases involved the temporal arteries. Emboli were documented in 125 eyes (62%). Systemic hypertension was common (132 patients or 71%). Although BRAO appears to be a relatively benign disease, its association with severe systemic conditions and documented increase in patient mortality suggests the need for careful evaluation by ophthalmologists.

Adolescent↗
PubMed1986

Naloxone does not antagonize the analgesic effects of inhalation anesthetics.

A previous demonstration that the ratio of analgesic to anesthetic endpoints is not constant across inhalation anesthetic agents implies that more than one mechanism of action may be operant in general anesthesia. We hypothesized that the endogenous opiate systems might account for this observed disparity in ratios. The tail flick ED50 (TFED50) in response to a heat stimulus, as an index of analgesia, and MAC as an index of anesthesia, were determined in rats treated with either saline or naloxone, 20 mg/kg, and exposed to halothane, enflurane, or isoflurane. Our findings confirmed those of Deady et al., showing a lack of uniformity of ratios of TFED50/MAC, with values of 0.90 +/- 0.03 for halothane, 0.80 +/- 0.04 for enflurane, and 0.70 +/- 0.04 for isoflurane. Naloxone had no effect on TFED50, MAC, or their ratio. If the endogenous opiate system were involved in the analgesic effect of general anesthetics, naloxone would have affected the ratios. We conclude that opiate systems are not involved in the analgesic action of general anesthetics.

Analgesia↗
PubMed1983

Recurrent microhyphema in the pseudophakic eye.

Although painless transient obscurations of vision are usually attributed to conditions affecting the posterior segment, careful slit-lamp, gonioscopic, and angiographic evaluations may establish an anterior segment origin for these symptoms. Recurrent hyphema, an uncommon late complication following routine cataract extraction, can be caused by spontaneous rupture of incisional vessels. In pseudophakic eyes, the uveitis-glaucoma-hyphema (UGH) syndrome and intermittent visual "white out" are late complications that may necessitate removal of the implant. The authors report five patients with uncomplicated extracapsular cataract extraction and implantation of a Binkhorst biplane, two-loop, capsule-fixated lens who presented with episodes of visual white out on the basis of iris bleeding. Argon laser photocoagulation to sites of iris leakage, at points of lens iris contact, resulted in prompt cessation of bleeding. Laser treatment appears to be a safe and effective alternative to removal of an otherwise satisfactory intraocular lens.

Aged↗