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Biomedical subjects

L F Moreira

Publications and source records attributed to L F Moreira.

At least 55 records · Page 3Linked to original sources

Kupffer cell function in chronic liver injury and after partial hepatectomy.

The reticuloendothelial system (RES) plays an important role in the biological defense system. In the liver, Kupffer cells are the main constituent of the RES, and when their function is impaired postoperative complications may more often occur. By using 99mTc-labeled human serum albumin millimicrospheres (99mTc-HSA-MM) combined with assessment of single photon emission computed tomography (SPECT), we have attempted to determine the function of Kupffer cells independently of the hepatic blood flow. First, Kupffer cell function in rats with chronic liver injury caused by CCl4 was studied. The hepatic uptake rate in chronic liver injury was decreased, and a reduced phagocytic activity of the Kupffer cells was noted. The parameter concerning Kupffer cell degradation, the excretion rate (k), was markedly decreased in the early period of chronic liver injury. Changes in Kupffer cell function after 30% and 70% hepatectomy were also studied. After 30% hepatectomy, the excretion rate was decreased on the first postoperative day (POD), and it was increased beyond that found after sham operation on the 3rd POD. In contrast, slower recovery of uptake rate was demonstrated. After 70% hepatectomy, both uptake and excretion rates were markedly reduced, and recovery was prolonged beyond the 5th POD. The hepatic uptake was not parallel with the excretion rate in either experiment. These results suggest that the method that measures the hepatic excretion rate may provide a better assessment of Kupffer cell function than the current uptake measurement with radiolabeled colloid.

Animals↗

Fetal heart block: a new experimental model to assess fetal pacing.

Epicardial fetal pacing via thoracotomy has the potential of being a safer and more reliable procedure to treat congenital complete heart block (CHB) associated with fetal hydrops refractory to medical therapy. To assess the acute electrophysiological characteristics of two ventricular epicardial leads, a new experimental model of fetal heart block induced by cryosurgical ablation of the AV node without the need for fetal cardiac bypass was performed in 12 pregnant ewes at 110-115 days gestation. A modified screw-in lead (1 1/2 turns) was used in six fetal lambs and a stitch-on lead in the other six lambs. CHB was achieved in 100% of the fetal lambs, with no ventricular escape rate noticed in any of the lambs. The acute stimulation thresholds were consistently low for both leads, with lower values for the screw-in lead at pulse duration below 0.9 msec (P < 0.03). Current measured at voltage threshold with pulse width below 0.5 msec was lower for the screw-in lead (P < 0.048). Stimulation resistance, measured during constant-voltage pacing, was not statistically different between the two leads (441.8 +/- 13.7 omega for the screw-in lead vs 480.2 +/- 59.2 omega for the stitch-on lead). No significant differences (P > 0.20) were found in R wave amplitude between the two electrodes. Slew rates were significantly higher in the screw-in group than in the stitch-on group (1.40 +/- 0.2 vs 0.62 +/- 0.2 V/sec, P = 0.04). This model of CHB is a simple and reproducible method to assess fetal pacing. We find the screw-in electrode to be a better option when fetal pacing is indicated.

Animals↗

Ovarian metastasis in patients with colorectal carcinoma.

The records of 159 patients who underwent surgical resection of colorectal cancer were reviewed to assess the incidence of ovarian metastasis and to define the role of oophorectomy. Four of these patients presented with metachronous metastases, and one patient had synchronous ovarian involvement. The incidence of ovarian involvement was higher in younger patients. While most patients with ovarian involvement had the primary tumor located at the rectosigmoid region, a similar distribution of the primary tumor was observed in patients without ovarian metastasis. The histological type and degree of differentiation was similar regardless of whether or not ovarian metastasis was present. Of the patient without ovarian metastasis, 57% presented with nodal metastases and 3.2% with peritoneal dissemination, while all patients with ovarian metastasis had nodal and peritoneal involvement. Our results suggest that histological type and degree of differentiation of the primary tumor do not influence likelihood of ovarian metastasis. However, the exposure of the tumor to the serosal surface and the subsequent peritoneal dissemination may be an important route by which malignant tumor cells reach the ovaries. However, due to the wide lymphatic involvement in patients with ovarian metastasis, the lymphatic route may be important as well. Thus, we consider that oophorectomy should be performed in all postmenopausal women, when the ovaries are macroscopically affected, and in premenopausal patients with Astler-Coller B2 tumors or over.

Adult↗

Cardiomyoplasty review: physiological principles and characteristics of electrically stimulated skeletal muscle. II. A therapeutic option.

Chronic heart failure continues unsolved as ever despite recent advances in cardiac surgery and pharmacological new armamentarium and remains a significant cause of death, regardless of etiology. Cardiomyoplasty (CMP), a new form of biomechanical ventricular support, has given new life to the field of mechanical circulatory support, providing a "bridge" to transplantation and serving as a possible alternative to surgical treatment. The geographic distribution of world experience in 401 patients shows that 80% were centralized in Europe (50%) and South America (30%). This review of the data analysis, documented improved changes in patients clinical status, further clarifies and appropriate patients population indications for DCMP as well as that more than 80% survival probability for NYHA class II & III and an early procedure related mortality of 8 to 10%.

Cardiomyopathy, Dilated↗

[Hemodynamic evaluation during isotonic exercise of patients with orthotopic heart transplantation].

PURPOSE: To evaluate the hemodynamic response of patients submitted to orthotopic heart transplantation during progressive isotonic exercise. METHODS: Eight patients who underwent orthotopic heart transplantation have been evaluated through invasive hemodynamic study during isotonic exercise. The mean right atrial pressure (RAP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), arterial blood pressure (ABP), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), heart rate (HR) and cardiac output (CO) have been determined in three distinct situations: at rest in the supine position (R), at rest with the legs up (RU) and during progressive isotonic exercise (E). The hemodynamic results at rest have been compared to the ones before transplantation. Phase RU and E results have been compared with each other. RESULTS: Comparing to the phase before transplantation at the R phase we found normalization of mean PAP (34.9 +/- 14.0 to 17.0 +/- 3.5 mmHg), RAP (7.3 +/- 4.3 to 2.9 +/- 1.9 mmHg) and CO (2.9 +/- 0.98 to 5.7 +/- 0.99 l/min), otherwise there was an increase in HR (89 +/- 15 to 94 +/- 13 bpm) mean ABP (84 +/- 25 to 115 +/- 12 mmH) and SVR (30 +/- 15 to 22 +/- 7 units Wood), (p < 0.05). Comparing phase E to phase RU, there was a significant increase in RAP (3.1 +/- 1.8 to 9.4 +/- 3.9 mmHg), mean PAP (21.0 +/- 2.8 to 37.0 +/- 10.0 mmHg), PAWP (8.1 +/- 2.1 to 15.0 +/- 5.8 mmHg), CO (5.8 +/- 0.8 to 9.9 +/- 2.4 l/min), HR (93 +/- 8 to 116 +/- 18 bpm) and a decrease in SVR (22.0 +/- 3.0 to 13.3 +/- 3.8 units Wood), (p < 0.05), otherwise there was no statistically significant modifications in PVR (2.2 +/- 0.7 to 2.3 +/- 1.2 units Wood) and mean ABP (129 +/- 12 to 129 +/- 15 mmHg), (p = NS). CONCLUSION: Patients submitted to heart transplantation may improve cardiac output mainly from increasing in stroke volume, associated with an increase in RAP and PAP. Nevertheless, the improvement increase in CO is compatible to exercise capacity after heart transplantation.

Adult↗

Magnetic resonance imaging evaluation of chronic changes in latissimus dorsi cardiomyoplasty.

BACKGROUND: Long-term clinical and hemodynamic benefits of dynamic cardiomyoplasty (DC) have been reported. However, no information is available about long-term morphological changes in the wrapped latissimus dorsi (LD) muscle in humans. METHODS AND RESULTS: The LD muscle flap was evaluated by magnetic resonance imaging (MRI) in 13 patients submitted to dynamic cardiomyoplasty for treatment of severe dilated cardiomyopathy. Eight patients were studied 15 days after the surgery (group 1) and 5 patients were studied from 24 to 52 months after the surgical procedure at the time of the cardiomyostimulator replacement (group 2). In the interim, LD was stimulated with burst of 6 pulses (duration, 185 milliseconds; burst frequency, 30 Hz) synchronized to every cardiac contraction, with a maximum of 100 LD contractions per minute. Images were acquired on a GE Sigma 1.5-T system (echo time, 25 milliseconds; repetition time, R-R x 2; slice thickness, 8 mm). The thickness of the LD decreased from 19.6 +/- 7.3 mm for group 1 to 7.6 +/- 0.8 mm for group 2 (P < .01). In addition, the signal intensity of the LD was compared with that of thoracic skeletal muscle and was found to be significantly increased in group 2 (2.19 +/- 0.42) compared with group 1 (1.04 +/- 0.07, P < .001). The signal intensity for group 2 on the T1-weighted images was similar to that of subcutaneous fat in those images. CONCLUSIONS: Morphological changes in the wrapped LD muscle consistent with fatty degeneration occur after DC and can be detected by MRI. Further studies will be necessary to demonstrate the clinical significance of such LD muscle flap changes.

Adipose Tissue↗

Arrhythmias and sudden death after dynamic cardiomyoplasty.

BACKGROUND: The main causes of death in patients with severe cardiomyopathy are progressive heart failure and sudden death. The influence of cardiomyoplasty on the incidence of sudden death and arrhythmias in patients with cardiomyopathy remains unclear. The aim of this study was to investigate the occurrence of arrhythmias and sudden death after cardiomyoplasty. METHODS AND RESULTS: We studied 32 patients (26 male, 6 female; mean age, 48 +/- 12 years) who submitted to cardiomyoplasty for treatment of heart failure in New York Heart Association (NYHA) class III (n = 24) or class IV (n = 8). The etiology was idiopathic dilated cardiomyopathy in 27 patients, ischemic heart disease in 3 patients, and Chagas' heart disease in 2 patients. Patients were routinely studied before and every 6 months after cardiomyoplasty by means of radioisotopic angiography and 24-hour Holter monitor recordings. There were no operative or immediate postoperative deaths. During the postoperative period, 5 patients presented with acute atrial fibrillation and 1 had an episode of sustained ventricular tachycardia. All episodes were successfully treated with intravenous antiarrhythmic drugs or cardioversion. During follow-up (from 2 to 66 months), 15 patients died from sudden death (n = 5) or progressive heart failure (n = 10). Survival rates at 1, 2, and 4 years were 79.9 +/- 7%, 62.5 +/- 9.7% and 35 +/- 12.1%, respectively. At 6-month follow-up, NYHA functional class improved from 3.2 +/- 0.4 to 1.7 +/- 0.6 (P = .001) and left ventricular ejection fraction increased from 19.8 +/- 3.3% to 24 +/- 8.2% (P = .004). The mean values per day of premature ventricular complexes (PVCs) and episodes of nonsustained ventricular tachycardia (NSVT) did not change statistically. The mean number of PVCs per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 126 +/- 44, 96 +/- 33, 90 +/- 29, 81 +/- 35, 71 +/- 35, and 59 +/- 48. The mean number of episodes of NSVT per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 3.3 +/- 1.3, 1.9 +/- 0.5, 1.3 +/- 0.5, 1 +/- 0.5, 1.5 +/- 1.1, and 0.6 +/- 0.5, respectively. With respect to analysis of the idiopathic dilated cardiomyopathy subgroup, there also were no significant differences in the incidences of pre- and postoperative arrhythmias. CONCLUSIONS: Despite NYHA functional class and left ventricular function improvements observed after cardiomyoplasty, the incidence of arrhythmias did not change, and sudden death was an important finding mainly in late follow-up. The problem of sudden death after cardiomyoplasty, the mechanism that produces it, and the means to prevent it remain critical areas for future research.

Arrhythmias, Cardiac↗

[Dynamics of patient selection for heart transplantation or cardiomyoplasty].

PURPOSE: To evaluate patient selection for heart transplantation or dynamic cardiomyoplasty. METHODS: We evaluated 380 patients from April 1991 to July 1993. The ages ranged between 16 and 68 (mean 43.5 +/- 11.46) years, 303 (79.7%) were male. The diagnoses were dilated cardiomyopathy in 163 (42.9%), Chagas' cardiomyopathy in 70 (18.4%), ischemic heart disease in 61 (16.1%), hypertensive heart disease in 40 (10.5%), valvular heart disease in 23 (6.1%), alcoholic cardiomyopathy in 12(3.2%), peripartum cardiomyopathy in 5 (1.3%) and myocarditis of unknown etiology in 5 (1.3%). RESULTS: The indication of heart transplantation was eventually done in 55 (14.4%), and 19 (5%) were submitted to transplantation. Dynamic cardiomyoplasty was indicated in 9 (2.3%) patients and was performed in 8 (2.1%). In 30 (7.8%) patients there were clinical contraindications for transplantation. Conventional surgical treatment was indicated for 12 (3.1%) patients: myocardial revascularization and/or ventricular aneurismectomy in 5, surgical treatment of valvular heart disease in 6 and of atrial fibrillation in 1. Socioeconomic limitations precluded transplantation in 43 (11.3%) and psychic limitations hindered transplantation in 23 (6.0%) patients. Refusal of procedure by the patient occurred in 10 (2.6%) cases. Improvement of the symptoms occurred in 69 (18.1%) patients. CONCLUSION: A small percentage of patients are eligible and are eventually submitted to heart transplantation or dynamic cardiomyoplasty. New strategies may be delineated during follow up, as deferring transplantation or conventional surgical treatment of ischemic or valvular heart disease. Sociopsychic evaluation is an important step in the care of the patients.

Adolescent↗

[Arrhythmias following orthotopic heart transplantation].

PURPOSE: To correlate the incidence of arrhythmias to the degree of allograft rejection on endomyocardial biopsy. METHODS: Seventeen patients who underwent orthotopic heart transplantation were submitted to ambulatory Holter monitoring 24h prior to endomyocardial biopsy. The biopsy results were compared to Holter monitoring results. RESULTS: The mean study period was 252 +/- 166 days (15 to 515). We found a high incidence of ventricular premature beats (> 70%), except in patients with severe rejection (25%), but there was no statistically significant difference between the groups with no rejection, mild and moderate rejection. Atrial premature beats were more common in patients with mild and moderate rejection (53% and 70%, respectively) when compared to patients with no rejection (33%) and patients with severe rejection (9%), (p < 0.05). Sinus bradycardia was present in 50% of patients with severe rejection, but only in 9% of moderate, 3% of mild and 5% of the patients with no rejection (p < 0.05). CONCLUSION: Supraventricular tachycardia and atrial premature beats are related to moderate rejection. Ventricular premature beats are not related to degree of rejection. Sinus bradycardia occurring in the first year after transplantation should suggest severe cardiac allograft rejection.

Arrhythmias, Cardiac↗

Cell cycle assessment of adoptive transferred lymphokine activated killer cells.

The use of lymphokine activated killer (LAK) cells for adoptive transfer therapy has been reported from number of clinical trials. To our knowledge, however, there has been no report concerning the cell cycle progression of LAK cells. Thus, for the present study we have attempted to examine the LAK cell cycle either before or after transfer. In vitro and in vivo analyses of LAK cells labeled with bromodeoxyuridine (BrdU) were carried out using two-parameter flow cytometries of their nuclear staining using fluorescein isothiocyanate(FITC)-conjugated anti-BrdU antibody and propidium iodide (PI). The in vitro growth of BrdU-positive cells showed the cells to divide once in the S phase, continue to the G2-M phase and return to the G0-G1 phase with a similar pattern after 48 or 72 h culture. They formed a definite subpopulation and were of phenotypes, thy-1.2 (+), Lyt-1.1 (-), Lyt-2.1 (+), L3T4 (-) and AGM1 (+). The percentage of BrdU-positive cells decreased significantly (P < 0.05) when treated with complement plus anti-thy-1.2, anti-Lyt-2.1 or anti-AGM1 anti-bodies, demonstrating BrdU-labeled LAK cells to have the same phenotype as control LAK cells. As in vitro, the in vivo cell cycle of LAK cells 48 and 72 h after transfer had a similar pattern, and the LAK cells also continued on to the S phase after the first division. The in vivo growth of the LAK cells treated with interleukin-2 (IL-2) was promoted 24 and 48 h after transfer. In conclusion, the present study showed LAK cells to be capable of dividing following transfer and to keep their own phenotypic characteristics; also, that treatment with IL-2 may promote their division. Adoptive transfer therapy seems to be a viable therapeutic method.

Animals↗

Current expectations in dynamic cardiomyoplasty.

Dynamic cardiomyoplasty has been evaluated in the treatment of severe cardiomyopathies. This report outlines the results of this procedure in 21 patients with dilated or ischemic cardiomyopathy who were in New York Heart Association class III or IV before operation. There were no operative deaths. Patients were followed up for a mean of 17.6 months. Eight patients died during late follow-up, and actuarial survival rates were 73.2% at 1 year and 65.9% at 2 years of follow-up. Functional class improvement was documented in the surviving patients. Furthermore, significant improvement in left ventricular function was demonstrated by radioisotopic angiography and by heart catheterization for more than 2 years after the operation. These studies documented that left ventricular ejection fraction increased as a result of global improvement in regional wall motion. Absence of clinical and hemodynamic improvement after cardiomyoplasty seems to be related to muscle flap ischemic compromise, whereas the patient's condition before operation seems to influence the long-term outcome of cardiomyoplasty.

Adolescent↗

Effects of thoracotomy on respiratory system, lung, and chest wall mechanics.

Nineteen rats were sedated, anesthetized, paralyzed, and mechanically ventilated. The respiratory, lung, and chest wall elastances (Est-rs, Est-L, Est-w); respiratory system, pulmonary, and chest wall total resistances (Rtot-rs, Rtot-L, Rtot-w); respiratory system, pulmonary, and chest wall initial resistances (Rinit-rs, Rinit-L, Rinit-w); and respiratory system, pulmonary, and chest wall difference resistances (Rdiff-rs, Rdiff-L, Rdiff-w) were determined before and after thoracotomy using the end-inflation occlusion method. Rinit reflects the Newtonian resistances and Rdiff represents the viscoelastic/inhomogeneous pressure dissipations in the system. Rtot = Rinit+Rdiff, ie, total resistance. The animals were submitted to either anterolateral thoracotomy (group A, n = 7), median sternotomy (group B, n = 6), or median sternotomy under PEEP while the lungs were exposed (group C, n = 6). In groups A and B, statistically significant increases in Rdiff-rs significantly augmented Rtot-rs. The former results were entirely secondary to significant increases in Rdiff-L, which naturally raised Rtot, L. Resistance was not altered in group C rats. Thus, anterolateral thoracotomy and median sternotomy increases Rtot-rs as a consequence of augmented Rdiff-L, but this finding could be prevented by the use of PEEP. Est-rs and Est-L increased in the three groups after surgery. Groups D and E were comprised of four animals each. Both underwent median sternotomy and in group E, PEEP was applied. Histopathologic examination of the lungs demonstrated a higher degree of lung collapse in group D.

Animals↗

Common bile duct injury during laparoscopic cholecystectomy.

Bile duct injury can occur more frequently during laparoscopic cholecystectomy than in open cholecystectomy. Three cases of common bile or hepatic duct injuries occurred in a series of eighty laparoscopic cholecystectomies; In case 1, the common bile duct was misidentified as the cystic duct. In case 2, bile peritonitis occurred on the fourth postoperative day caused by necrosis of the common hepatic duct involving the cautery surrounding it. In case 3, a bile leak occurred due to an incision at the confluence of the cystic and common duct. Dissection of the cystic duct at the infundibulum of the gallbladder, blunt dissection of the Calot's triangle, the handling of clips with special attention for safety were thought to be necessary in order to lower the risk of bile duct injury. Preoperative endoscopic retrograde cholangiography (ERCP) is recommended to avoid bile duct injury.

Adult↗

Inhibition of liver regeneration in mice following extended hepatectomy by transfusion of lymphokine activated killer cells.

Lymphokine activated killer (LAK) cells can destroy not only tumor cells but also syngeneic liver cells. In this study, the effects of passive transfer of LAK cells on liver regeneration were examined by the 3H-thymidine uptake and bromodeoxyuridine (BrdU) labeling methods after resection of 70% of the volume of the liver. LAK cells were infused 12h after hepatectomy and the effects on regeneration of liver cells were examined 36 h later. The transfusion of LAK cells induced significant inhibition of liver regeneration at a dose of 5-10 x 10(7) cells. Neuraminidase treatment of lymphocytes is desirable to enhance the selective entrapment of LAK cells into the liver. When LAK cells were treated with neuraminidase (0.5 units/ml), and transfused into hepatectomized mice, more potent suppression of liver regeneration was induced in comparison with the same dose of LAK cells. The intraperitoneal injection of recombinant interleukin 2 (rIL-2) after partial hepatectomy also inhibited the regeneration of remnant liver. From these results, lymphocytes such as LAK cells appear to regulate liver regeneration.

Animals↗

Blood cardioplegia with warm reperfusion versus intermittent aortic crossclamping in myocardial revascularization. Randomized controlled trial.

To compare the efficiency of two methods of myocardial protection--blood cardioplegia and warm reperfusion with aspartate-glutamate enrichment of the solution versus intermittent aortic crossclamping--we randomized 60 patients for coronary artery bypass grafting. Hemodynamic parameters and hospital mortality were the end points. Pathologic antecedents and preoperative clinical conditions were similar in both group I (blood cardioplegia, 30 patients) and group II (aortic crossclamping, 30 patients). An average of 2.9 grafts per patient were performed in group I and 3.1 in group II. Duration of extracorporeal circulation was 100 +/- 28 minutes in group I and 85 +/- 23 minutes in group II (p < 0.05). The total time of aortic crossclamping was 62.8 +/- 24.5 minutes in group I and 44.3 +/- 14.9 minutes in group II (p < 0.05). There were comparable increases in cardiac index in group I and group II from the preoperative period to the first postoperative day, but none of these changes reached statistical significance. There were two deaths, one in the cardioplegia group (3.3%) and another in the intermittent aortic crossclamping group (3.3%). In conclusion, in myocardial revascularization, intermittent aortic crossclamping and blood cardioplegia with warm reperfusion enriched with aspartate-glutamate solution are methods of similar efficiency.

Aorta↗

Late effects of cardiomyoplasty on left ventricular mechanics and diastolic filling.

BACKGROUND: Dynamic cardiomyoplasty is a relatively new surgical procedure proposed for treatment of severe myocardial failure. Limited clinical experience suggests that this procedure reverses congestive heart failure, improving the long-term survival. METHODS AND RESULTS: In this investigation, the late effects (16.5 +/- 4.8 months after surgery) of cardiomyoplasty on left ventricular mechanics and diastolic filling were studied in eight male patients (mean age, 45 +/- 7 years). The investigation was performed with the myostimulator on and off (24 +/- 1 hours off) using a microtip catheter to obtain the left ventricular pressures simultaneously with Doppler (inflow velocities) and M-mode and two-dimensional echocardiographic recordings. Statistical comparisons were made with Student's t test for paired data. Dynamic cardiomyoplasty increased the maximal elastance (17 +/- 1 versus 21 +/- 1 mm Hg/cm, P = .006) and decreased the systolic wall stress (253 +/- 17 versus 190 +/- 12 g/cm2, P = .029). Left ventricular end-diastolic pressure decreased (27.1 +/- 2.8 versus 17.6 +/- 1.7 mm Hg, P = .019), as did end-diastolic circumferential wall stress (69 +/- 8 versus 37 +/- 5 g/cm2, P = .002). The chamber and muscle stiffnesses decreased (120 +/- 31 versus 52 +/- 11 mm Hg/cm, P = .017; 994 +/- 185 versus 426 +/- 76 g/cm2, P = .002, respectively). The pattern of left ventricular diastolic filling changed, with a decrease of early peak flow (231 +/- 20 versus 217 +/- 21 mL/s, P = .022), of deceleration time (163 +/- 28 versus 116 +/- 26 seconds, P = .001), and of flow area during rapid filling (105 +/- 15 versus 75 +/- 12 mL, P = .004) and an increase of flow area during atrial contraction (39 +/- 4 versus 88 +/- 9 mL, P = .001). CONCLUSIONS: Our detailed evaluation of left ventricular mechanics demonstrates that cardiomyoplasty has significant multiple beneficial effects on dilated myopathic heart.

Assisted Circulation↗