Biomedical subjects

L Pablo

Publications and source records attributed to L Pablo.

15 recordsLinked to original sources

PubMed2001

Optimum criteria for short-wavelength automated perimetry.

OBJECTIVE: To determine the optimum perimetric criteria for short-wavelength automated perimetry on the basis of probabilistic maps that best discriminate between normal and glaucoma. DESIGN: Comparative cross-sectional study. PARTICIPANTS: Ninety-five glaucomatous eyes and 128 normal eyes were included in the study. INTERVENTIONS: The subjects underwent retinal nerve fiber layer photographic evaluation and short-wavelength automated perimetry. MAIN OUTCOME MEASURES: A probabilistic map of differential points for short-wavelength automated perimetry was elaborated, and the number of altered points was calculated for each visual field and level of significance (95%, 98%, 99%, and 99.5%). RESULTS: The presence of a cluster of four or more points outside 95% normal probability limit showed a good combination of sensitivity and specificity. At deeper levels, P: < 1% and P: < 0.5%, the best combination is achieved with three points outside the normal probability limits. CONCLUSIONS: The optimum criterion to define glaucomatous abnormalities in short-wavelength automated perimetry is the presence of a cluster of four points lower than P: < 5% or a cluster of three points lower than P: < 1%.

Adult↗

PubMed2001

Latanoprost versus combined therapy with timolol plus dorzolamide: IOP-lowering effect in open-angle glaucoma.

PURPOSE: To compare the effect on intraocular pressure of latanoprost versus timolol plus dorzolamide in open-angle glaucoma. METHODS: Thirty-five patients with open-angle glaucoma were randomized, 18 to latanoprost once daily and 17 to timolol plus dorzolamide twice daily. Intraocular pressure and ocular side effects were recorded at baseline, and after 2 weeks and 3 months of treatment. RESULTS: Latanoprost reduced the intraocular pressure 1.09 and 1.58 mm Hg more than timolol plus dorzolamide after 2 weeks and 3 months of treatment, respectively. These differences were statistically significant (p<0.05) at the end of the study. After 3 months of treatment, 32.3% of the eyes in the latanoprost group reduced the intraocular pressure in 30% or more with respect to baseline, while 15.6% of the eyes in the timolol plus dorzolamide group achieved this reduction. CONCLUSIONS: Latanoprost administered once daily reduced the intraocular pressure at least as well as timolol plus dorzolamide twice daily in patients with open-angle glaucoma.

Adrenergic beta-Antagonists↗

PubMed2000

Cloning and analysis of the gene encoding the human neonatal Fc receptor.

The neonatal Fc receptor, FcRn, is expressed in human placental syncytiotrophoblast, capillary endothelium, intestinal epithelium, and other tissues. By analogy with its role in the mouse, human FcRn is expected to transport maternal IgG to the foetus, and protect circulating IgG from catabolism. The larger subunit of FcRn is homologous to the alpha chains of the major histocompatibility complex (MHC) class I proteins, but is encoded outside the MHC on chromosome 19. We report the isolation of clones encoding the alpha chain of human FcRn from chromosome 19-specific libraries. The sequence revealed a similar organization to classical and non-classical MHC, and MHC-related genes. Compared with classical MHC class I genes, the human FcRn alpha chain gene has expanded by acquiring many repetitive sequences in its introns, including multiple Alu elements in the fourth intron. Primer extension analysis showed that there are two transcription initiation sites in the upstream flanking sequence.

Amino Acid Sequence↗

PubMed2000

[Nd-YAG capsulotomy and intravitreal antibiotics as treatment of chronic endophthalmitis].

PURPOSE: To study the effectiveness of Yag capsulotomy, therapeutic vitreal aspiration and intravitreal injection of antibiotics combination on the treatment of chronic postoperative endophthalmitis. METHODS: Six patients with symptoms of refractory postoperative endophthalmitis after extracapsular cataract extraction, with an intraocular lens were treated following a protocol that included: YAG capsulotomy, vitreal aspiration and intravitreal injection of antibiotics. RESULTS: In four cases -66%- the micro-organism was isolated -three cases of coagulase- negative staphylococci and one case Corynebacterium spp. In all the cases the inflammatory process decreased, and a noticeable improvement of visual acuity was achieved. No recurrent cases were observed (two patients died before the end of the study). CONCLUSIONS: As way of conclusion we can state that the initial capsulotomy allows the destruction of the infection reservoir in order to eradicate the agent. This endophthalmitis therapeutic alternative is effective, easy and reliable for the ophthalmologist.

Aged↗

PubMed1999

Effect of inhaled beta 2 adrenoceptor agonist, albuterol sulphate, on performance of horses.

This study was designed to test the hypothesis that a specific beta 2 adrenergic receptor agonist, albuterol sulphate, when delivered by metered-dose inhaler (MDI) would affect the performance of Thoroughbred horses during incremental exercise testing. Six conditioned Thoroughbred horses were randomly assigned to one of 2 treatment groups: Group 1 horses received placebo and Group 2 received albuterol. Each horse received both treatments in a crossover design with a 3 week interval between trials. Horses inspired albuterol (900 micrograms) or placebo over a 5 min period followed by an incremental, peak oxygen consumption (VO2peak) exercise test. Facial arterial blood gases (PaO2, PaCO2), pHa, temperature, haemoximetry (O2Hb, COHb, MetHb, RHb) and electrolytes (Na+, K+, iCa2+, Cl-) were measured. Heart rate (HR), VO2peak, CO2 production (VCO2), plasma lactate, speed at failure, exercise duration, and urine levels of albuterol and metabolites (Alburine) were monitored. The Paratrend7 intravascular sensor provided continuous arterial blood gas data. Mixed effects linear modelling using generalised least-squares estimation was used to assess treatment and speed main effects interaction. Significant differences (P < 0.01) were found between placebo and albuterol-treated horses for total run time (mean +/- s.e. 405.8 +/- 8.8 vs. 430.5 +/- 6.7 s) and run time from completion of 8 m/s until fatigue (169.3 +/- 8.6 vs. 187.3 +/- 6.7 s), as well as VO2peak (121.7 +/- 3.7 vs. 130.3 +/- 3.8 ml/kg/min), respectively. In conclusion, inhaled albuterol sulphate has a small but significant effect on the performance of fit Thoroughbred horses during incremental, VO2peak exercise testing.

Administration, Inhalation↗

PubMed1997

Use of Trp mutations to evaluate the conformational behavior and membrane insertion of A and B chains in whole diphtheria toxin.

The structure of diphtheria toxin was examined using its Trp fluorescence. To examine the interactions of the A and B chains of the toxin independently, mutants were constructed in which Trp residues were restricted to either the A or the B chain. The conformation and stability of the mutants were very similar to those of the wild-type protein. In addition, they underwent the low-pH conformational transition and membrane insertion at about the same pH as wild-type toxin. This shows Trp do not play a critical role in these processes which are necessary for the translocation of toxin across endosomal membranes in vivo. There was a shift in fluorescence of the Trp mutants which showed the low-pH-induced transition increases exposure of both the A and B Trp to a more polar environment. This supports a model in which the interdomain interactions present at neutral pH break down at low pH. To evaluate the location of the A and B chains in the membrane, the fluorescence quenching of model membrane inserted toxin was measured. Comparison of the amount of quenching by lipid labeled with nitroxides localized at shallow, medium, or deep depths within the bilayer demonstrated that both the A and B chains insert deeply, but the A chain Trp are somewhat less deeply inserted. Trp on the A chain are also less exposed to lipid than on the B chain, as judged by their weaker quenching by the nitroxide-labeled lipid. This conclusion was supported by the observation that the Trp of membrane-inserted isolated A chain is more lipid-exposed than when the A chain is part of the whole toxin. Both the A and B chain Trp become less exposed to lipid after neutralizing pH. However, both chains remain inserted, with at least part of the B chain remaining deeply inserted. These results support the "partial wrapper" model in which both the A and B chains are inserted but contacts between the two chains significantly reduce the exposure of the A chain to lipid.

Diphtheria Toxin↗

PubMed1997

Intravenous and oral pharmacokinetic evaluation of a 2-hydroxypropyl-beta-cyclodextrin-based formulation of carbamazepine in the dog: comparison with commercially available tablets and suspensions.

Complexation of carbamazepine with 2-hydroxypropyl-beta-cyclodextrin was performed to provide improved formulations of this widely used antiepileptic drug. Based on this approach, liquid dosage forms were configured for both parenteral and oral use. Intravenous administration of an aqueous carbamazepine x 2-hydroxypropyl-beta-cyclodextrin (CBZ x HPbetaCD) complex at a CBZ dose of 20 mg/kg was well tolerated and generated high initial drug levels that fell monoexponentially as a function of time, yielding a plasma elimination half-life of 38 min. Oral studies were completed with three preparations: a commercially available tablet and suspension, as well as a CBZ x HPbetaCD oral solution. Oral administration of tablets gave erratic and slow absorption, leading to maximum CBZ concentrations (C(max)) of <2 microg/mL, which were manifested only at 2.5 h after drug dosing. The absolute bioavailability of CBZ from the tablets was approximately 25%. Both the suspension and CBZ x HPbetaCD solution gave a significantly improved profile. Thus, the liquid oral dosage forms approximately doubled the oral bioavailability of CBZ compared with the tablets.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed1996

Hyperkalemic periodic paralysis episode during halothane anesthesia in a horse.

A 7-month-old Quarter Horse filly was admitted for surgical repair of a right olecranon fracture. Anesthesia was achieved with xylazine hydrochloride, guaifenesin, ketamine hydrochloride, and halothane. Two and a half hours after induction of anesthesia, myotonia, muscle fasciculations, and sweating, concurrent with high serum potassium concentration and associated electrocardiographic changes consistent with hyperkalemic periodic paralysis, were observed. Treatment included intermittent positive-pressure ventilation, changing intravenous administration of fluids from lactated Ringer's solution to 0.9% NaCl solution, and administration of calcium gluconate, glycopyrrolate, dopamine, and sodium bicarbonate. Clinical signs resolved with the return of serum potassium concentrations to the reference range. The horse was confirmed to be heterozygous for hyperkalemic periodic paralysis by DNA testing.

Anesthesia, General↗

PubMed1995

A major histocompatibility complex class I-related Fc receptor for IgG on rat hepatocytes.

Intestinal epithelial cells of the neonatal rat and mouse have been shown to express a major histocompatibility complex (MHC) class I-like Fc receptor, or FcRn, which transports IgG in an apical to basolateral direction. Previous studies have suggested the possible expression of this receptor beyond the neonatal period within the liver. Since bile contains high levels of IgG, we sought to determine whether the FcRn was functionally expressed by adult rat hepatocytes. Using primers specific for FcRn, which did not cross hybridize with MHC class I transcripts, FcRn DNA was amplified by reverse transcriptase polymerase chain reaction from RNA of adult rat hepatocytes. This RNA contained functional FcRn transcripts as it encoded a beta 2-microglobulin-associated cell surface protein as determined by immunoprecipitation of biotinylated cell surface proteins with a polyclonal anti-FcRn specific antiserum. Western blotting of hepatocyte canalicular (apical) and sinusoidal (basolateral) plasma membranes with an FcRn-specific monoclonal antibody further confirmed the protein expression and suggested that FcRn was enriched on the canalicular surface membranes. FcRn, on the surface of hepatocytes, was biologically functional as it bound Fc fragments of IgG at pH 6.0 but not 8.0, which is the same pH dependence observed for FcRn in rat neonatal enterocytes. Thus, FcRn is functionally expressed outside of the neonatal period on the canalicular cell surface of adult hepatocytes. This suggests that hepatocyte FcRn may bind luminal IgG, providing a potential functional communication between parenchymal immune cells and bile.

Animals↗

PubMed1994

Electrophysiological methods in early glaucoma detection.

Electrophysiological methods like pattern electroretinogram and pattern visual evoked potentials may be the best approach for early glaucoma detection, as they have demonstrated to be sensitive to the ganglion cells functional changes. Reported values of both P50 and N95 pattern electroretinogram components differ widely, a fact perhaps related to a heterogeneous grouping of patients suffering from ocular hypertension and glaucoma, rather than to the type of technique utilized. This study is based on a total of 42 subjects: 14 normals, 16 subjects suffering from ocular hypertension, and 12 patients with glaucoma, with 79 eyes examined. Pattern electroretinogram and pattern visual evoked potentials were used as successive techniques. Setting condition for pattern electroretinogram, such as low temporal frequency (2 Hz), 30 min check size, high contrast (99%) and luminance (93 cd/m2), identified the N95 component as the best index for early glaucoma detection. In the control group N95 mean amplitude was 1.62 muV +/- 0.59 SD and showed almost significant difference with ocular hypertension (p = 0.07) and highly significant difference with the glaucoma group (p < 0.01), with decrement of 58.6% in the glaucoma group. P50 mean amplitude, on the contrary, did not show significant differences among the groups (Newman-Keul test), its reduction in glaucoma being 28%. The mean pattern visual evoked potentials latency was alos highly significant between glaucoma and control groups, but not between ocular hypertension and control groups; the mean amplitude did not show significant differences. A proportion of 26.6% abnormal pattern electroretinogram was found in the group suspected of having glaucoma where conventional methods had proved normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiology↗

PubMed1990

Comparative study of ultrasonography and arteriography of the carotid artery of xylazine-sedated and halothane-anesthetized goats.

The carotid artery of clinically normal goats was examined, using duplex ultrasonography and arteriography. The diameter of the carotid artery was measured by use of two-dimensional ultrasonography and Doppler ultrasonography, respectively, before and after xylazine administration. The diameter of the artery was also measured by use of an arteriography technique in halothane-anesthetized goats. There was no significant difference between the mean diameter of the carotid artery measured by ultrasonography in conscious nonsedated goats and that determined by arteriography in goats under halothane anesthesia. On the other hand, ultrasonography of xylazine-sedated goats revealed an increase of carotid artery diameter of 20 to 30%. There was no change in the velocity of blood flow after xylazine administration.

Anesthesia↗

PubMed1989

The pony as an animal model for vascular implants.

This study evaluated the pony as a potentially suitable model for vascular implant research. Healthy, conditioned ponies were randomly assigned to one of three groups: group I, carotid artery autografts (n = 6); group II, e-PTFE carotid interpositional grafts (n = 5); and group III, e-PTFE carotid interpositional grafts plus aspirin (10 mg/kg) and dipyridamole (3.5 mg/kg) drug administration. It was found that autografts remained patent longest (mean = 396.2 days; grafts were still patent at time of writing) followed by group III grafts (157.5 days), with group II grafts remaining patent for the shortest duration (61.1 days), (p less than 0.01). Patency was determined using two-dimensional real-time ultrasonography with Doppler velocimetry and/or arteriography. It was demonstrated that the pony's response to antithrombotic drugs was consistent and comparable to that in other animal models, both with respect to platelet function and affect on patency rate. The combination of the ease of surgical manipulation, drug administration, and platelet function testing, the comparable size of the pony and its heart and blood vessels to that of an adult human, the long life span of ponies, and the patency results of this study have demonstrated that the pony is a valuable animal model for vascular research.

Animals↗

PubMed1988

Platelet function testing in the pony.

Platelet isolation techniques and platelet function were evaluated in 35 adult ponies. Platelet recovery from whole blood was consistent and the preparation of platelet rich plasma was facilitated by an enhanced erythrocyte sedimentation rate. All platelet samples aggregated in response to 10 microM ADP. However, concentrations of ADP as high as 100 microM did not elicit significant 14C-serotonin release. Collagen induced irreversible platelet aggregation and 14C-serotonin release in all samples. The threshold dose for collagen in most ponies was 1.5 micrograms. Arachidonic acid (500 microM) failed to induce irreversible platelet aggregation or 14C-serotonin release in any of the samples evaluated. Pony platelets were nonresponsive to epinephrine (5.5 microM).

Adenosine Diphosphate↗

PubMedDate not supplied

Short-wavelength automated perimetry and neuroretinal rim area.

PURPOSE: To determine the correlation between neuroretinal rim area and functional losses detected by short-wavelength automated perimetry (SWAP) in a population of patients with suspected glaucoma. METHODS: Forty-two eyes of 42 ocular hypertensive subjects who met the selection criteria (intraocular pressure greater than 21 mm of Hg and normal conventional visual fields) were studied. A planimetric optic nerve head study was performed, determining the total and sectorized neuroretinal rim areas. SWAP was also done, with a modified Humphrey field analyzer. RESULTS: There were no significant correlations between the neuroretinal rim areas and the global perimetric parameters. However, the correlations between the inferotemporal neuroretinal rim area and some superonasal visual field regions (areas 3 and 4) were significant. CONCLUSIONS: There is a relation in the topography of some visual field areas assessed by SWAP and the inferotemporal neuroretinal rim area, which may play a role in the diagnosis and follow-up of suspected glaucoma.

Adult↗

PubMedDate not supplied

Granular dystrophy associated with congenital cataracts.

Seven members of the same family suffering from Groenow I granular dystrophy and associated congenital cataracts have been studied. Three patients had corneal dystrophy at various stages and three others had a fetal nuclear congenital cataract. A penetrating keratoplasty button was studied under light and electron microscopies. This association has not been described previously. However we must emphasize that there is no general validity for a correlation between granular dystrophy and congenital cataract.

Adolescent↗