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At least 613 records · Page 34Linked to original sources
PubMed2003

An experimental model of rhegmatogenous retinal detachment: surgical results and glial cell response.

PURPOSE: To modify existing experimental models to simulate the typical clinical presentation of human rhegmatogenous retinal detachment (RRD), namely an RD caused by a retinal break, in a phakic eye, with a posterior vitreous detachment (PVD); to model RRD in a species that is anatomically similar to humans; and to characterize the glial cell response to RRD. METHODS: Mixed-breed pigs underwent vitrectomy, PVD, subretinal injection of viscoelastic, and creation of a break at the apex of the RD. The crystalline lens was not removed. Follow-up was for 0, 1, and 7 days. Tissue was processed for light and electron microscopy. The glial cell response was characterized using antibodies to glial fibrillary acidic protein (GFAP). RESULTS: Of 11 RRDs created in seven pigs, 10 increased in size and 1 decreased. Light and electron microscopy demonstrated typical features of RD. There was constitutive expression of GFAP in astrocytes and Müller cells with increased immunoreactivity from day 1. CONCLUSIONS: This study provided a model of RRD that simulates the typical clinical presentation in humans. It used techniques that most vitreoretinal surgeons are familiar with, and an animal that is widely available and anatomically similar to humans. Anatomic success was high, and the glial cell response established comparability with other species.

Animals↗
PubMedDate not supplied

[Experimental model of orthotopic uterus transplantation in the laboratory rat].

This study develops and standardizes an experimental model of uterus transplantation in the laboratory rat. Twelve orthotropic uterus transplantation were done. Animals were randomized in three groups. Postoperative survival was 100% and 75% at 72 hours. Recipients were euthanased at 24 hours, 48 hours and 72 hours and the grafts were harvested. Patency of the microsurgical anastomoses was 100% at 24 hours, 63% at 48 hours and 0% at 72 hours. The explanted uterine grafts were fixed in formalize and analyzed under light microscopy. The acute allograft rejection starts during the second day after transplantation. In additional dissection, anatomy of the pelvic region with regard to the topography of the uterus, tube and ovarian vessels was studied. This model of uterus transplantation in rats proposes a standardized tool for further research regarding cellular mechanisms of the acute allograft rejection and, for future, pregnancy of the transplanted uterus.

Animals↗
PubMedDate not supplied

[Comparative activities of ciprofloxacin, amoxicillin, and cotrimoxazole in an experimental model of enteritis caused by Salmonella non typhi].

With the use of an in vitro experimental model of enteritis by Salmonella non typhi the efficacy of amoxicillin, cotrimoxazole and ciprofloxacin in the eradication of this fecal pathogen and the prevention of bacteremia was evaluated. Following a fasting period of 48 hours a total of 160 rats were administered 10 UFC of 2 strains of Salmonella non typhi via intragastric tubing. One of the strains was sensitive to amoxycillin and cotrimoxazole (60 rats) and the other strain was resistant to both but was sensitive to ciprofloxacin (100 rats). The antimicrobials were administered 24 hours after the bacterial infection in daily doses for 5 consecutive days. According to the results obtained amoxicillin and cotrimoxazole were ineffective in the eradication of the fecal pathogen indicating an important obstacle in the appearance of bacteremias. To the contrary, ciprofloxacin, even at low doses, eliminated the microorganisms early and demonstrated high efficacy in the prevention of bacteremia in the animals when these results were compared with those of the untreated group.

Amoxicillin↗
PubMed1992

An experimental model for subclinical edema disease (Escherichia coli enterotoxemia) manifest as vascular necrosis in pigs.

An experimental model for subclinical edema disease was developed in weanling pigs. In multiple experiments, 3-week-old pigs were weaned, then inoculated intragastrically with 10(10) colony-forming units of an SLT-IIv-positive strain of Escherichia coli originally isolated from a pig with edema disease (principals). Control pigs were inoculated with a nonpathogenic E coli strain. Of 39 principals, 8 developed clinical edema disease within 14 days after inoculation. However, 20 of 21 principals that did not develop clinical signs of edema disease, but were submitted for necropsy examination at 14 days after inoculation, had characteristic vascular lesions of edema disease. Vascular lesions, found principally in ileum and brain, consisted of segmental necrosis of myocytes in the tunica media of small arteries and arterioles. None of the pigs inoculated with a nonpathogenic strain of E coli developed edema disease or vascular lesions. None of the principals necropsied at 2 days after inoculation had vascular lesions. Development of vascular lesions by 14 days after inoculation was used as the end point for detecting subclinical edema disease in the model.

Animals↗
PubMed1984

Assessment of optimal dose of diuretic associated with fixed dose of beta-blocking: a new experimental model based on multiple sampling of blood pressure performed by self-measurements.

A new experimental model is presented for determining the optimum dose of 3 different doses (13 mg, 25 mg, 37 mg per day) of hydrochlorothiazide employed to enhance hypotensive effect of 200 mg/day of metoprolol in human hypertension. The model takes into account the circadian variability of blood pressure as sinusoidal function and wash-out effect as a linear trend so as to compensate for bias due to normal temporal variability.

Adrenergic beta-Antagonists↗
PubMed1983

[Experimental model for the detection of leukemia-specific antigens in acute leukemias in humans].

An experimental model for demonstration of leukospecific antigens is offered: immunization of animals with leukemic cells from the same patient followed by examination of antisera and performance of adsorption within the autologous system of the same patients suffering from acute leukemia. It has been found that antigenic spectrum of leukemic cells and lymphocytes within the histoidentical system of the same patient varies: the leukemic cells bear additional antigens on their surface whereas mature lymphocytes had none of them. The lack of possibility to compare additional antigens with differentiating antigens enables one to term them as leuko-associated rather than leukospecific antigens.

Animals↗
PubMed1984

Experimental models of chronic alcoholism, solid diet versus liquid diet.

The liquid diet and solid diet experimental models of chronic alcoholism were compared. The intake of food and the growth of rats were recorded for 24 days. All the alcoholic animals receiving either liquid or solid diet consumed adequate amounts of protein, fat, carbohydrate, salts and vitamins, and showed normal development. However the alcoholic animals given solid diet consumed more calories (total), more calories as alcohol and showed early adaptation to the diet in comparison to alcoholic animals that received the liquid diet.

Alcoholism↗
PubMed1997

Encephalocele: experimental model. Morphogenesis, pathogenesis and clinical correlations discussion.

RESEARCH OBJECT: This study intends to consider an encephalocele experimental model, obtained in embryonate eggs, treated in a post-neurulation phase with chemical teratogens. This study intends to point out possibility that pathogenic process, which have determined a malformation, is referable to an original defect of embryonic cranial coatings development and that neurulation defect is secondary. EXPERIMENTAL PLAN: Chick and duck embryonate eggs have been used. They have been inoculated in their development phase with known chemical teratogens, as Dintoina and Blue Trypan. A controlling group has been inoculated with physiological solution and, then, it has been followed till the hatching. The experimental group has been undergone to artificial hatching, according to prearranged conditions and it has been analysed during different phases of its development. MEASURES: Four cranioencephalic malformations have been obtained: three cases of encephalocele and one case of exencephalia. The individual pathological compounds have been studied under the morphological and histopathological profile. The skull base dimensions have been taken and then compared with the controlling group ones. CONCLUSIONS: In the light of experimental data, some considerations have been undertaken considering the pathogenetic hypothesis findable in medical literature, stressing the possibility that encephalocele may be arranged as a post-neurulation defect and that, for taxonomic aims, it has to fit in a different group within cranial disraphims.

Animals↗
PubMed1985

Chronic effects of alcohol on the epithelium of the small intestine using two experimental models.

The effects of chronic alcohol ingestion on the rat small intestinal epithelium have been measured using two different experimental models, viz. either a solid diet plus alcohol or a liquid diet plus alcohol. All experimental animals consumed adequate quantities of food and exhibited a normal growth rate; thus the recorded effects were unlikely to be associated with malnutrition. After a period of 24 days, there were significant decreases in the jejunal villus cell population in both groups of experimental animals and corresponding increases in the crypt cell populations; no such changes were found in the ileum. Alcohol had no significant effect on the crypt cell production rate and the growth fraction at either of these two sites in the intestine, and thus the major effect of alcohol was to cause a lengthening of the cell cycle time in the jejunal crypts.

Alcoholism↗
PubMed1992

An experimental model for simultaneous quantitative analysis of pulmonary micro- and macrocirculation during unilateral hypoxia in vivo.

An experimental model was developed for quantitative analysis of pulmonary microcirculation using in vivo fluorescence videomicroscopy during unilateral hypoxia induced by one-lung ventilation (1 LV). In five white New Zealand rabbits, pulmonary arterioles on the surface of the right lung were visualized by means of intra-arterial injection of FITC-labeled erythrocytes and FITC-Dextran. During 1 LV of the left lung, the mean airway pressure in the right lung was kept at the level of two-lung ventilation (2 LV) by means of N2-CPAP. Arteriolar diameters as well as parameters of macrocirculation (AP, CVP, PAP, LAP, CO) and gas exchange (paO2, Qs/Qt) were measured simultaneously during 2 LV and 1 LV. FiO2 was kept constant at 1.0 during both experimental phases. Macrohemodynamic parameters during 1 LV did not differ from those measured during 2 LV. 1 LV induced a significant decrease in paO2 (213 +/- 105 versus 427 +/- 22 mm Hg, P < 0.05) and a significant increase in Qs/Qt (22 +/- 7 versus 13 +/- 2%, P < 0.05). During 2 LV (baseline), the pulmonary arteriolar diameters ranged from 15-120 microns. 1 LV resulted in a significant decrease of arteriolar diameters to 89.0 +/- 9.3% of baseline (P < 0.05). Relative changes in arteriolar diameters were similar for vessels with baseline diameters of 0-40, 40-60, and 60-120 microns (88.4 +/- 9.9%, 89.6 +/- 9.4%, and 88.4 +/- 8.7%, respectively). The present model is the first one allowing in-vivo investigation of HPV during 1 LV and 2 LV on the basis of simultaneous measurement of pulmonary arteriolar diameters and macrocirculatory parameters in vivo. Although PAP and PVR did not change significantly, a reduction of pulmonary arteriolar diameters was proven in response to alveolar hypoxia during 1 LV. We suggest the model to be useful in studying the physiological effects of HPV on macro- and microcirculation as well as investigating pathophysiological and pharmacological influences on HPV.

Animals↗
PubMed2001

Eptifibatide and abciximab exhibit equivalent antiplatelet efficacy in an experimental model of stenting in both healthy volunteers and patients with coronary artery disease.

Platelet deposition and aggregation are the major determinants of acute thrombosis in coronary stents. We aimed to compare the antiplatelet efficacy of different treatments--glycoprotein (Gp) IIb/IIIa inhibitors and conventional antiaggregants--in an experimental model for stenting. Blood samples were obtained from patients with coronary artery disease (n = 15) and healthy volunteers (n = 8) and incubated either with eptifibatide (2.0 microg/ml), abciximab (3.0 microg/ml), indomethacin (15 microg/ml), or saline. Platelet adenosine diphosphate-induced aggregation in whole blood was assessed for all groups. Blood was also tested in an experimental circulation model containing metallic probes, on which platelet deposition in shear flow conditions was assessed by means of fluorescent-labeled platelet-specific (anti-GpIIIa and Ib) antibodies. Eptifibatide and abciximab, in comparison with indomethacin and no treatment, significantly reduced platelet aggregation (0, 0, 4, and 3 arbitrary units [AU], respectively; p < 0.001), anti-GpIIIa (2.25, 1.83, 11.24, and 13.42 counts per second [cps]/mg, respectively; p < 0.001), and anti-GpIb binding (0.61, 0.61, 1.00, and 1.83 cps/mg, respectively; p < 0.001). Anti-GpIIIa and anti-GpIb binding were significantly correlated (R = 0.36; p < 0.01). Patients showed a higher anti-GpIIIa, but not anti-GpIb binding, than controls (8.43 versus 3.33 cps/mg; p < 0.01), irrespective of treatment. In conclusion, eptifibatide and abciximab show equivalent in vitro antiplatelet efficacy, superior to that of indomethacin. Given the occurrence of GpIIb/IIIa platelet overexpression in the course of coronary artery disease, an extended use of GpIIb/IIIa inhibitors may be proposed to prevent acute thrombosis during routine coronary stenting.

Abciximab↗
PubMed1994

Experimental models for quantitative studies on adhesion formation in rats and rabbits.

Postoperative formation of adhesions is a common complication in abdominal surgery. The aim of the present study was to develop standardized experimental models for quantitative studies of the formation of adhesions in rats and rabbits. In rats the suturing of a peritoneal wound increased adhesion formation significantly compared to leaving it open, 77.9 +/- 4.8 and 5.3 +/- 2.8%, respectively (p < 0.001). The suturing technique, when comparing the interrupted and continuous method after 1 week, had no influence, 84.5 +/- 6.3% and 73.1 +/- 11.2%, respectively (p > 0.05). Different types of trauma resulted in differences in adhesion formation to noninjured parts in the abdominal cavity, adhesions in 17.5 and 2.5% of the animals, respectively (p < 0.05). In rabbits adhesions formed more frequently (p < 0.001) to visceral peritoneum (59.3 +/- 3.7%) than to the parietal one (22.3 +/- 1.6%) indicating a different propensity of tissues to have adhesions. These models enable detailed quantitative studies on experimental formation of adhesions.

Animals↗
PubMedDate not supplied

[The development of a new experimental model of pneumocystosis].

The corticosteroid tricort-40 (triamcinolone acetonide) was found to induce the reactivation of endogenous pneumocystic injection caused by P. carinii in Wistar rats given 5-9 infections subcutaneously in median doses of 0.5-4.0 mg/kg at 6-22 days intervals each. Manifest P. carinii infection in the animals was characterized by early detection of its agent (starting from week 2 of immunosuppression), a progression of the infection and its transition to the generalized stage. The combined use of tricort-40 and infection of the animals with Leishmania infantum as an immunosuppressive cofactor ensured an increase in reproducibility of a manifest pneumocystosis model and its more rapid transition to the generalized stage. The experimental model of mixed infection of two AIDS-associated parasite infections--generalized pneumocystosis and visceral leishmaniasis--was first reproduced in inbred rats, which may be suitable for simultaneous screening of new antipneumocystic and antileishmanial drugs.

Animals↗
PubMed1978

Release of endotoxin in an experimental model simulating the dental root canal.

The action of endotoxin on subcutaneous connective tissue was examined in an experimental model simulating the dental root canal. The local Shwartzman reaction was used as a tool to detect slight tissue alterations that might otherwise go unobserved. The experimental results warrent, in our opinion, the tentative conclusion that the primary toxicity of endotoxins has no major part in the initiation or maintenance of chronic periapical inflammation.

Animals↗
PubMed1998

Cardiac lymphatic dynamics after ischemia and reperfusion--experimental model.

ABSTRACT. The aim of the present study was to investigate the lymphatic cardiac circulation in an experimental model of ischemia plus reperfusion in mongrel dogs (Canis familiaris L). As radiotracer we used 0.2-0.25 ml (111 MBq) of 99mTc-Re2S7 colloid (+/-10 microm), injected subcapsullary below the second diagonal of the descending anterior ligated coronary artery with a special needle. A gamma-camera/Starport + DecStation were used for data acquisition. Four experimental groups with five animals each were established: G I = controls; G II = immediately after acute myocardial infarction (AMI); G III = late infarction (5 days after AMI); G IV = ischemia (90 min) + reperfusion. Four regions of interest (ROIs) were chosen: injection area (ZA), above (ZB), near right (ZD), and far right (ZC) from ZA. Mean disappearance times in ZA and dynamic parameters in the other ROIs were determined from activity/time curves drawn in each area, using homemade software. The results obtained seem to indicate that the methodology is appropriate to a detailed study of lymphatic drainage in pathological situations in animal models.

Animals↗
PubMed1999

Measurement of insertion torque of tapered external fixation pins: A comparison between two experimental models.

The aim of this study was to compare an in vitro versus an ex vivo experimental model to test the insertion torque of two different types of external fixation pins. A torque measuring machine was developed in order to perform accurate measurements. Forty tapered pins made of stainless steel were utilized. Half of the pins were plasma-spray coated with hydroxyapatite (HA) and the other half remained uncoated. For the in vitro model 20 cylinders were used that were made of synthetic polymer according to ASTM standards. For the ex vivo model 10 fresh femora harvested from adult sheep were used. All the pins were implanted after predrilling, and insertion torque was measured. Statistical analysis of the in vitro versus the ex vivo model showed significant differences in both coated (p < 0. 0005) and uncoated (p = 0.002) external fixation pins. These results may be due to the surface roughness that caused significant friction between the HA coating and the polyvinylchloride in the in vitro model. The significant difference between the in vitro and ex vivo results lead us to state that the in vitro model does not realistically simulate the behavior of external fixation pins implanted in bone.

Animals↗
PubMed1992

Comparative study of six antifungal treatments in an experimental model of murine cryptococcosis.

A comparative study, using 5 antifungal drugs for the treatment of an experimental model of murine cryptococcosis, was carried out. One hundred and eighty Balb C mice, divided in 18 groups of 10 animals each, were intraperitoneally inoculated with 10(7) cells of Cryptococcus neoformans var. neoformans. Twelve groups were treated with different schedules beginning 5 days after inoculation, for 2 or 4 weeks. The treatments were the following: amphotericin B (6 mg/kg/every other day, intraperitoneally); 5-fluorocytosine (300 mg/kg/day, by gavage); amphotericin B (6 mg/kg/every other day, intraperitoneally) in association with 5-fluorocytosine (300 mg/kg/day, by gavage); fluconazole, itraconazole and Sch 39.304 (all at the daily dose of 16 mg/kg, by gavage). The six remaining groups were used as controls and received the solvent for the drugs. The evaluation of the efficacy of the different treatments was based on: survival time; macroscopy of brain, lungs, liver and spleen at autopsies; presence of encapsulated yeasts in microscopic examination of wet preparations of these organs; and cultures of a concentrated suspension of brain and lungs. In the animals treated for 2 weeks, the combination of amphotericin B + 5-fluorocytosine was the most useful; it negativized the micro and macroscopic findings as well as 90% of the cultures, and prolonged the survival time up to 60 days. Sixty per cent of the mice which received amphotericin B exhibited the same survival time and macroscopic findings as those treated with the association of amphotericin B + 5-fluorocytosine. Among the azolic compounds, Sch 39.304 proved to be the most effective in the prolongation of survival time.(ABSTRACT TRUNCATED AT 250 WORDS)

Amphotericin B↗
PubMed1986

Development of an experimental model of acute myocardial infarction and the effects of a thromboxane synthetase inhibitor (OKY-046).

An experimental model of acute myocardial infarction is presented. Intracoronary thrombus was precipitated by a mock ruptured atheromatous plaque, which is a cholesterol-collagen mixture, protruding into the stenosed left anterior descending coronary artery. Twenty-five dogs, divided into two groups, were studied: a control group of 15 dogs and a treated group of 10 dogs. Intracoronary thrombus was precipitated by the mock atheromatous plaque in 13 of 15 control animals. Myocardial infarction was induced in 10 and sudden death in two. Coronary blood flow decreased gradually or cyclically to end in myocardial infarction. The model was utilized to investigate the effects of a thromboxane synthetase inhibitor, OKY-046, on 10 additional animals. OKY-046 could significantly decrease the incidence of occlusive thrombus formation and myocardial infarction when administered intravenously during coronary blood flow reduction (3 of 10 in the treated group vs 12 of 15 in the control group, p less than 0.02). Thromboxane B2 was significantly elevated in the coronary venous blood during reduction of the coronary blood flow, while thromboxane B2 was reduced and 6-ketoprostaglandin F1 alpha increased during OKY-046 administration. The reduction in thromboxane A2 production associated with increased prostacyclin appeared to be the major mechanism of the interruption of the thrombus formation by OKY-046.

6-Ketoprostaglandin F1 alpha↗