Myocardial contractility of the isovolumetrically beating isolated rat heart

Several indexes of myocardial contractility have been proposed to assess ventricular function in the isovolumetrically beating isolated heart. However, the conclusions reached on the basis of these indexes may be influenced by ventricular geometry rather than contractility itself. The objective of the present study was to assess the performance of widely used contractility indexes in the isovolumetrically beating isolated heart in two experimental models of hypertrophy, the spontaneously hypertensive rat (SHR) and infrarenal aortocava fistula. Compared to normotensive controls (N = 8), SHRs with concentric hypertrophy (N = 10) presented increased maximum rate of ventricular pressure rise (3875 ± 526 vs 2555 ± 359 mmHg/s, P < 0.05) and peak of isovolumetric pressure (187 ± 11 vs 152 ± 11 mmHg, P < 0.05), and decreased developed stress (123 ± 20 vs 152 ± 26 g/cm², P < 0.05) and slope of stress-strain relationship (4.9 ± 0.42 vs 6.6 ± 0.77 g/cm²/%). Compared with controls (N = 11), rats with volume overload-induced eccentric hypertrophy (N = 16) presented increased developed stress (157 ± 38 vs 124 ± 22 g/cm², P < 0.05) and slope of stress-strain relationship (9 ± 2 vs 7 ± 1 g/cm²/%, P < 0.05), and decreased maximum rate of ventricular pressure rise(2746 ± 382 vs 3319 ± 352 mmHg, P < 0.05) and peak of isovolumetric pressure (115 ± 14 vs 165 ± 13 mmHg/s, P < 0.05). The results suggested that indexes of myocardial contractility used in experimental studies may present opposite results in the same heart and may be influenced by ventricular geometry. We concluded that several indexes should be taken into account for proper evaluation of contractile state, in the isovolumetrically beating isolated heart.

Heart transplantation experiences: a phenomenological approach

Aim. The aim of this study was to understand the heart transplantation experience based on patients' descriptions.Background. To patients with heart failure, heart transplantation represents a possibility to survive and improve their quality of life. Studies have shown that more quality of life is related to patients' increasing awareness and participation in the work of the healthcare team in the post-transplantation period. Deficient relationships between patients and healthcare providers result in lower compliance with the postoperative regimen.Method. A phenomenological approach was used to interview 26 patients who were heart transplant recipients. Patients were interviewed individually and asked this single question: What does the experience of being heart transplanted mean? Participants' descriptions were analysed using phenomenological reduction, analysis and interpretation.Results. Three categories emerged from data analysis: (i) the time lived by the heart recipient; (ii) donors, family and caregivers and (iii) reflections on the experience lived. Living after heart transplant means living in a complex situation: recipients are confronted with lifelong immunosuppressive therapy associated with many side-effects. Some felt healthy whereas others reported persistence of complications as well as the onset of other pathologies. However, all participants celebrated an improvement in quality of life. Health caregivers, their social and family support had been essential for their struggle. Participants realised that life after heart transplantation was a continuing process demanding support and structured follow-up for the rest of their lives.Conclusion. The findings suggest that each individual has unique experiences of the heart transplantation process. To go on living participants had to accept changes and adapt: to the organ change, to complications resulting from rejection of the organ, to lots of pills and food restrictions.Relevance to clinical practice. Stimulating a heart transplant patients spontaneous expression about what they are experiencing and granting them the actual status of the main character in their own story is important to their care.

Comparison of synthetic hydroxyapatite and porous polyethylene implants in eviscerated rabbit eyes

Purpose: Synthetic hydroxyapatite and porous polyethylene (Polipore) spheres were placed in rabbits' eviscerated cavities to evaluate tissue reaction and volume maintenance.Methods. Fifty-six Norfolk albino rabbits underwent unilateral evisceration and implantation of synthetic hydroxyapatite (H group, 28 animals) or porous polyethylene spheres (P group, 28 animals). Postoperative reactions, animal behavior, and socket conditions were monitored. Light microscopy and morphometric evaluation with statistical analysis of the exenterated orbits were performed at 7, 15, 30, 60, 90, 120, and 180 days. Scanning electron microscopy was appraised 7, 60, and 180 days after surgery.Results: Two animals from the H group and 1 from the P group had extrusion 7 days after surgery. Throughout the experimental period, the synthetic hydroxyapatite caused more inflammation than the porous polyethylene material. Ingrowth in the sphere occurred 7 to 15 days after the surgery in both groups, and the tissue reaction became denser at approximate to60 to 90 days, when bony metaplasia began in the H group. Volume maintenance was better in the P group and with a smaller pseudocapsule surrounding the implanted sphere than in the H group.Conclusions: Clinical findings demonstrated mild inflammation inside the sphere and in the pseudocapsule surrounding it and better cavity volume maintenance in the P group animals. The authors consider porous polyethylene a more suitable material than synthetic hydroxyapatite for use in anophthalmic cavity reconstruction.

Effects of Inhaled Nitric Oxide on Oxidative Stress and Histopathological and Inflammatory Lung Injury in a Saline-Lavaged Rabbit Model of Acute Lung Injury

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

High-frequency oscillatory ventilation attenuates oxidative lung injury in a rabbit model of acute lung injury

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Development of a rabbit's urethral sphincter deficiency animal model for anatomical-functional evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Autologous transplantation of adult adipose derived stem cells into rabbit urethral wall

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of intravenous propofol and remifentanil on heart rate, blood pressure and nociceptive response in acepromazine premedicated dogs

ObjectiveTo investigate the cardiorespiratory, nociceptive and endocrine effects of the combination of propofol and remifentanil, in dogs sedated with acepromazine.Study designProspective randomized, blinded, cross-over experimental trial.AnimalsTwelve healthy adult female cross-breed dogs, mean weight 18.4 +/- 2.3 kg.MethodsDogs were sedated with intravenous (IV) acepromazine (0.05 mg kg-1) followed by induction of anesthesia with IV propofol (5 mg kg-1). Anesthesia was maintained with IV propofol (0.2 mg kg-1 minute-1) and remifentanil, infused as follows: R1, 0.125 mu g kg-1 minute-1; R2, 0.25 mu g kg-1 minute-1; and R3, 0.5 mu g kg-1 minute-1. The same dogs were administered each dose of remifentanil at 1-week intervals. Heart rate (HR), mean arterial pressure (MAP), respiratory rate (f(R)), end tidal CO(2) (Pe'CO(2)), arterial hemoglobin O(2) saturation, blood gases, and rectal temperature were measured before induction, and 5, 15, 30, 45, 60, 75, 90, and 120 minutes after beginning the infusion. Nociceptive response was investigated by electrical stimulus (50 V, 5 Hz and 10 ms). Blood samples were collected for plasma cortisol measurements. Statistical analysis was performed by anova (p < 0.05).ResultsIn all treatments, HR decreased during anesthesia with increasing doses of remifentanil, and increased significantly immediately after the end of infusion. MAP remained stable during anesthesia (72-98 mmHg). Antinociception was proportional to the remifentanil infusion dose, and was considered satisfactory only with R2 and R3. Plasma cortisol concentration decreased during anesthesia in all treatments. Recovery was smooth and fast in all dogs.Conclusions and clinical relevanceInfusion of 0.25-0.5 mu g kg-1 minute-1 remifentanil combined with 0.2 mg kg-1 minute-1 propofol produced little effect on arterial blood pressure and led to a good recovery. The analgesia produced was sufficient to control the nociceptive response applied by electrical stimulation, suggesting that it may be appropriate for performing surgery.

Reproductive responses of rabbit does to a supplemental lighting program

The objective was to investigate whether the productivity of rabbit does can be improved, when natural photoperiod is decreasing, by adopting a supplemental lighting program. Three experiments were conducted involving two groups: control, submitted to the natural decreasing photoperiod, and supplemented with a lighting program which provided 14 h light/24 h beginning at 10 weeks of age. In the first experiment, 20 nulliparous does, 10 from each group, were euthanized 8 h after being presented to a buck; the overall number of follicles, whose diameter exceeded I mm, was determined macroscopically. The right ovaries were collected, histologically analyzed, and electronically measured. In the second experiment, 30 nulliparous does, 15 from each group, were presented to a buck (day 1). Receptive does were euthanized on day 8 to evaluate embryonic survival (number of normal embryos/ovulation rate). In the third experiment, 48 nulliparous does, 24 from each group, were followed from the first presentation to the buck until the weaning of the first litter. The effect of treatment on reproductive and body weight traits of does, and litter performance traits, at birth and weaning, was evaluated. The average number of follicles whose diameter exceeded 1 mm was higher in the treatment group (12.05 +/- 1.07 vs. 8.63 +/- 1.00, P=0.03 7). Receptive does of the treatment group had heavier ovaries relative to those of the control group (790 +/- 59 vs. 470 +/- 64 mg, P=0.004), whereas no treatment difference regarding this trait was found for non-receptive ones. Treatment had a favorable effect on pregnancy rate of total exposed and of receptive does (80.0% vs. 33.3%, P=0.01, and 92.3% vs. 50.0%, P=0.02, respectively). The number of underdeveloped embryos was lower (0.067 +/- 0.380 vs. 2.500 +/- 0.455, P=0.004), embryonic survival up to day 8, and uterus weight was higher in the treatment group (0.839 +/- 0.075 vs. 0.534 +/- 0.087, P=0.033 and 13.83 +/- 0.72 vs. 10.99 +/- 0.84, P=0.037, respectively). Number of presentations tended to be lower (1.32 +/- 0.17 vs. 1.75 +/- 0.16, P=0.077) and adjusted litter size in the first reproductive cycle tended to be higher (7.09 +/- 0.89 vs. 5.22 +/- 0.68, P=0.091) in the treatment group relative to the control.