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J R Ortiz

Publications and source records attributed to J R Ortiz.

At least 19 recordsLinked to original sources
PubMed1999

[Utility of double burst stimulation in the detection of residual neuromuscular blockade].

OBJECTIVE: To assess the usefulness of double burst stimulation (DBS) for detecting neuromuscular blockade caused by atracurium and vecuronium. PATIENTS AND METHODS: One hundred nineteen adult patients were randomly assigned to receive atracurium (n = 62) or vecuronium (n = 57), with electromyographic monitoring of the number of responses to train of four (TOF) stimuli, TOF-ratio (TR) and the amplitude of the first TOF response (T1) in the pollicis adductor and the response to neurostimulator DBS in the contralateral forearm. During recovery from neuromuscular blockade an independent anesthesiologist manually assessed two responses to DBS every minute as being clearly differentiated, doubtful or undifferentiated. The results were later compared to T1 and TR. RESULTS: Significant differences (p < 0.05) between groups were observed for TR in doubtful (0.27 +/- 0.18 and 0.34 +/- 0.17 for atracurium and vecuronium, respectively) and undifferentiated (0.34 +/- 0.22 and 0.43 +/- 0.18, respectively) responses to DBS, and for T1 with three TOF responses (26.0 +/- 13.6 and 33.1 +/- 14.2, respectively) or four responses (30.9 +/- 14.1 and 38.7 +/- 18.4, respectively). T1 values when TR was 0.75 (extubation criterion) were 68.1 +/- 23.8% and 60.5 +/- 17.4% for the atracurium and vecuronium groups, respectively (NS). CONCLUSIONS: Assuming that DBS reduces the risk of residual curarization and that a TOF-ratio greater than 0.75 indicates adequate recovery from neuromuscular blockade, manual assessment of DBS response as obtained in this study indicates curarization and equal responses do not guarantee its absence. The most reliable index of recovery from neuromuscular blockade is the TR obtained by electromyographic monitoring.

Adult↗
PubMed1997

[Mivacurium].

Mivacurium is a short-acting nondepolarizing muscle relaxant (NDPMR) with a benzyl-isoquinoline structure and rapid, spontaneous reversal. It is hydrolyzed by cholinesterase in plasma and its chemical structure favors histamine release, leading to cutaneous or cardiovascular symptoms, particularly when the dose is increased or when the drug is injected rapidly. Both duration of effect and reversal of mivacurium are less dose dependent than they are with intermediate-duration NDPMRs. In adults the recommended dose for intubation (2 to 3 times the ED95) induces clinically effective blockade lasting 15 to 25 minutes, with spontaneous recovery occurring 10 to 20 minutes later. In children two to 12 years old given the same dose, duration of action is shorter and reversal occurs more rapidly. These properties reduce the likelihood of antagonizing the residual neuromuscular blockade. The duration of successive doses is similar and continuous infusion does not affect reversal. Neuromuscular blockade may be prolonged in patients with low plasma cholinesterase activity, particularly in individuals who are homozygous for the atypical plasma cholinesterase gene. Monitoring is therefore recommended when mivacurium is used. Provided patients have normal plasma cholinesterase activity, mivacurium is indicated for interventions that are short or of unpredictable duration when rapid reversal of neuromuscular blockade is required, or whenever anticholinesterase agents must be avoided.

Age Factors↗
PubMed1995

[Latex allergy in anesthesiology].

Allergy to latex, described 15 years ago, is increasing. It affects mainly certain risk groups, such as health-care workers and patients with spina bifida or genitourinary malformations. Symptoms vary in intensity from mild to life-threatening and can present during any medical procedure involving skin or mucosal contact, or inhalation, of the allergen in a previously sensitized patient. The most serious cases reported have generally involved patients undergoing surgery. Prevention is based mainly on tentative diagnosis made when the patient's history is taken, followed by laboratory tests and consultation with an allergist. Because prophylactic drug protocols have proven ineffective, the patient must be offered a latex-free environment in keeping with standard recommendations.

Allergens↗
PubMed1994

Inhibition of proliferating lens epithelium with antitransferrin receptor immunotoxin.

We investigated the effect of an antitransferrin receptor immunotoxin (454A12-rRA) on proliferating human and baboon lens epithelium in vitro. Human and baboon lens epithelial cells grown in modified TC-199 medium at 35 degrees Celsius in 7% CO2 were seeded in 24 well plates at a density of 17,500 cells/ml to 40,000 cells/ml. The cells were exposed to various concentrations of 454A12-rRA for seven days. The sensitivity of proliferating human lens epithelium to 454A12-rRA was dependent on the dose, with a 60% to 70% reduction in cell counts at immunotoxin concentrations of 100 ng/ml and above. The immunotoxin had no significant effect on baboon lens epithelium in vitro, which suggests that it is specific for human tissue. By preventing the proliferation of human lens epithelial cells, immunotoxin 454A12-rRA may be useful in the management of posterior capsule opacification after planned extracapsular cataract surgery.

Animals↗
PubMed1994

Effects of 3-nitrobenzothiazolo[3,2-a]quinolinium chloride (NBQ) and doxorubicin on lens regeneration in the adult newt: a morphological study.

The antitumor drug 3-nitrobenzothiazolo [3,2-a] quinolinium chloride (NBQ) stimulates the in vivo lens regeneration in the adult newt Notophthalmus viridescens and induces a differentiated state in HL-60 leukemia cells. Because the cytotoxic drug doxorubicin (Adriamycin) induces differentiation of HL-60 cells in vitro we decided to compare the effect(s) of doxorubicin with NBQ on lens regeneration in vivo. Both drugs were injected intraperitoneally at six different schedules. Morphological criteria of the different regeneration stages were used in the analysis of the regenerates. NBQ stimulated lens regeneration independently of the time intervals and the stage of regeneration at which the drug was administered. There was an increase in the mean number of mitoses suggesting that NBQ stimulated cell proliferation. Doxorubicin administered for five days did not modify the regenerative process. On the other hand, doxorubicin given for periods of nine or more days after lentectomy, strongly inhibited the formation of a new lens. Thus, the inhibitory effect of doxorubicin is dependent on the continuous long term contact with the tissue. Although NBQ and doxorubicin are both DNA intercalators, they induced the effects on lens regeneration through different mechanisms.

Animals↗
PubMed1992

Sclerokeratoplasty with maintenance of the angle.

Using sclerocorneal dissection and angle-support sutures to maintain the angle and its function, we performed 14-mm sclerokeratoplasty with placement of allograft tissue in five eyes of 15 patients. One previously operated-on eye required a second sclerokeratoplasty and three eyes required secondary optical keratoplasty after opacification of the original large graft. Patients were monitored from 11 to 90 months postoperatively. At the last examination, all patients had clear grafts and visual acuity had improved since the preoperative examination. All patients had intraocular pressure maintained within normal range (less than 22 mm Hg, as measured by pneumotonometry) except for two patients in whom transient increases were resolved by tapering of corticosteroid treatment. Our results suggested that sclerokeratoplasty, using angle-support sutures, is an effective treatment for diffuse destructive corneoscleral disease that cannot be managed with a smaller graft.

Adult↗
PubMed1992

Analysis of opsin mRNA and protein expression in adult and regenerating newt retina by immunology and hybridization.

Rod photoreceptor cells were analysed in adult and regenerating Notophthalmus viridescens retinae using a combination of immunochemical and molecular biological approaches. Monoclonal anti-rhodopsin antibody (Rho-4D2) labelled rod but not cone photoreceptors in adult newt retinae. The antibody bound to the entire cell body, from the synaptic ending through to the outer segment, as examined by light and electron immunocytochemistry. The antibody labelled two bands of 35 and 56 kDa in Western blots of urodele retinal preparations separated by gel electrophoresis. In situ hybridization with radiolabelled anti-sense riboprobes specific for bovine opsin revealed intense patches of silver grains overlying approximately 50% of photoreceptor inner segment myoid regions; no signal above background was detected elsewhere in the retina, or with radiolabelled sense riboprobe controls. Northern blot analysis using the probe on poly A(+) mRNA of adult newt retinae indicated a single band of 1.5 kb, corresponding to the opsin transcript. Following surgical removal of the original retina in test animals, retinal regeneration was studied by sampling tissue from 0-50 days post-surgery. The reappearance of opsin immunoreactivity was examined by light microscopical techniques. No opsin expression was detected in regenerating tissue prior to 16 days. Subsequent to this time, rho-4D2 bound to cells in central areas in which substantial lamination of the new retina had already occurred, and was limited to the scleral border. At no time was any immunoreactivity observed in more peripheral undifferentiated tissue. Thus the reformation of a functional retina seems to follow the same control mechanisms as during development, photoreceptor redifferentiation being at least partly governed by positional or environmental cues.

Animals↗
PubMed1992

Immunocytochemical study of extracellular matrix components during lens and neural retina regeneration in the adult newt.

We have conducted an immunocytochemical study of fibronectin, laminin, heparan sulfate proteoglycans and nidogen-entactin during lens and neural retina regeneration in the adult newt from 0 to 60 days. In the normal eye, fibronectin was detected in the corneal stroma and Descemet's membrane, in dorsal and ventral irises and lens capsule but not in Bowman's membrane of the cornea. In normal neural retina, fibronectin was found in Bruch's and inner limiting membranes. Heparan sulfate proteoglycans gave a slight signal in both irises and the lens capsule. Nidogen-entactin distribution in the cornea was similar to that of fibronectin; it was absent from the stroma of both irises, and the signal was weak in the pigmented iris epithelium. Nidogen-entactin was not detected in the lens capsule and inner limiting membrane of the neural retina but was present in Bruch's membrane. During the first 15 days of lens regeneration, fibronectin and nidogen-entactin decreased but did not disappear from the pupillary margin of both irises, and no signal was obtained for laminin and heparan sulfate proteoglycans. From day 15 to day 60 fibronectin and nidogen-entactin increased in both irises and lens capsule. The signal for laminin was restricted to the lens capsule. Heparan sulfate proteoglycans gave a slight signal in both irises and in the lens capsule. During the first 25 days of neural retina regeneration, fibronectin was the first to appear in Bruch's membrane and the cell border of the new neuroepithelium and remained during the entire process. Laminin appeared after 41 days in the inner limiting and Bruch's membranes, but by day 50 it appeared as a weak signal only in the inner limiting membrane. Heparan sulfate proteoglycans were not detected at any of the regeneration stages studied. Nidogen-entactin was only detected in Bruch's membrane and around the cells and blood vessels of the new neural retina. Later it was detected in the inner limiting membrane but not in Bruch's membrane. Thus, the results obtained showed that extracellular matrix components do change during both lens and neural retina regeneration. These changes may play an important role during both regenerating processes.

Animals↗
PubMed1991

CREST-associated multiple intracranial aneurysms and bilateral optic neuropathies.

A patient with a clinical and serological diagnosis of CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal motility abnormalities, sclerodactyly, telangiectatic lesions), a variant of PSS (progressive systemic sclerosis), was found to have multiple intracranial aneurysms. She subsequently developed bilateral optic neuropathies. Ischemic and compressive etiologies are proposed and related to the histopathology of the patient's underlying systemic disease.

Aged↗
PubMed1988

The effect of catecholamines and adenosine on the induction of morphological alterations and depigmentation of newt iris epithelial cells in vitro.

Catecholamines and adenosine have a stimulating effect on the process of dedifferentiation of cultured iris epithelial cells (IECs) from the adult newt Notophthalmus viridescens. Micromolar concentrations of adrenergic ligands such as isoproterenol, norepinephrine, and epinephrine induced marked morphological alterations culminating in the stellate configuration and depigmentation of IECs. Dopamine at 100 microM or higher induced the morphological response, while serotonin was ineffective. The morphological change was transient, requiring 80-90 min for maximum induction, and only a fraction of the cells was responsive. The response was blocked by beta-adrenergic antagonists, such as propranolol and alprenolol, but not by alpha-adrenergic blockers. Adenosine at 10 microM, or higher, also induced morphological alterations of IECs. The effect of adenosine was partially blocked by various adenosine receptor antagonists. The effect of isoproterenol and norepinephrine on the induction of morphological alterations was potentiated by adenosine. The release of melanosomes from IECs was increased in the presence of catecholamines and adenosine. Catecholamines and adenosine at 10 microM increased the intracellular levels of cAMP of dedifferentiating dorsal irides. The increase in cAMP levels induced by isoproterenol was inhibited by propranolol and the adenosine receptor antagonist 5'-deoxy-5'-methyl thioadenosine (MTA) partially blocked the effect of adenosine. Our results suggest that adrenergic hormones may be coupled to a beta-adrenergic adenylate cyclase system. The presence of an adenosine receptor is also suggested by the results. Our data strongly support previous work in which cAMP and substances related to it induced morphological alterations and depigmentation of IECs. It is proposed that catecholamines and adenosine may participate in the regulation of dedifferentiation during the transdifferentiation of IECs into lens cells.

Adenosine↗
PubMed1987

The antitumor drug 3-nitrobenzothiazolo(3,2-a)quinolinium chloride (NBQ): effects on lens regeneration and interaction with DNA of Notophthalmus viridescens.

We have studied the effect of 3-nitrobenzothiazolo(3,2-a)quinolinium (NBQ) on the regeneration of the lens in adult newt Notophthalmus viridescens. NBQ has marked cytotoxic effects in tumor cells, intercalates DNA, and was found to enhance lens regeneration. Newt liver DNA was isolated, and the thermal denaturation temperature (Tm) determined to be 76.6% +/- 0.8%. The G-C content was determined to be 44.0% +/- 0.4% and 45.0% +/- 0.1%. Parameters of NBQ binding to newt DNA were determined by spectrophotometric methods and compared with those obtained for calf thymus and Micrococcus lysodeikticus. The association constant, K(o), was found to be 1.1 x 10(+5) M-1 with a site-size parameter, n, of 8.7 nucleotides. No explanation is apparent for the paradoxical stimulation of lens regeneration.

Animals↗
PubMed1973

Induction of the stellate configuration in cultured iris epithelial cells by adenosine and compounds related to adenosine 3':5'-cyclic monophosphate.

Adenosine, dibutyryl cyclic AMP, monobutyryl cyclic AMP, cyclic AMP, and 5'-AMP have a remarkable morphogenetic effect on cultured iris epithelial cells obtained from adult newt. They alter the broad undulating membrane of the cell into branching strands of cytoplasm, a configuration that has been named "stellate." Theophylline, a phosphodiesterase inhibitor also induces the stellate configuration. This transient morphological alteration is detectable by 30 min and becomes maximal 80 min after treatment. In the continued presence of the effective compounds the altered cells return to their normal shape, although the recovery period is variable. The morphological alteration of iris epithelial cells in vitro observed in the present experiment is reminiscent of that which occurs during the dedifferentiation phase in lens regeneration in vivo. These observations suggest that induction of the stellate configuration is relevant to the mechanism of dedifferentiation of newt iris epithelial cells during Wolffian lens regeneration.

Adenosine↗