Heat stress elicits different responses in peripheral blood mononuclear cells from Brown Swiss and Holstein cows.

This study was undertaken to assess whether peripheral blood mononuclear cells (PBMC) isolated from Brown Swiss (Br) and Holstein (Ho) cows and stimulated with concanavalin A differ in response to chronic exposure to incubation temperatures simulating conditions of hyperthermia. Five multiparous Br and 5 Ho cows were utilized as blood donors. Peripheral blood mononuclear cells were subjected for 65 h to each of 5 treatments (T). Cells were exposed to 39 degrees C continuously (T39) and three 13-h cycles at 40 (T40), 41 (T41), 42 (T42) or 43 degrees C (T43), respectively, which were interspersed with two 13-h cycles at 39 degrees C. Treatment T39 was adopted to mimic normothermia; T40, T41, T42, and T43 mimicked conditions of more severe hyperthermia alternating with normothermia. Measures evaluated at the end of the incubation period were proliferative response (DNA synthesis), intracellular reactive oxygen species (ROS) concentrations, and mRNA abundance of the 72-kDa heat-shock protein (Hsp72). In Br cows, DNA synthesis began to decline when PBMC were repeatedly exposed to 41 degrees C (-22%), whereas DNA synthesis in cells isolated from Ho cows did not begin to decline until 42 degrees C (-40%). Furthermore, under T41 and T42, DNA synthesis from Br cows was lower than in Ho(-24 and -54%, respectively). In both breeds, increased incubation temperatures caused a reduction of intracellular ROS (from -39.6 and -69.7%). Increase in incubation temperatures enhanced Hsp72 mRNA levels only in PBMC isolated from Br cows. The Hsp72 mRNA in Br cows increased significantly under T41 and T43 compared with T39. In both breeds, DNA synthesis was positively and negatively correlated with intracellular ROS and Hsp72 mRNA abundance, respectively (r = 0.85 and r = -0.70, respectively). Results indicated that PBMC from Br cows are less tolerant to chronic heat exposure than those from Ho cows, and that the lower tolerance is associated with higher expression of Hsp72, suggesting that the same level of hyperthermia may be associated with a differential decline of immune function in the 2 breeds.

In vitro effects of nonesterified fatty acids on bovine neutrophils oxidative burst and viability.

An in vitro study was conducted to examine the influence of nonesterified fatty acids (NEFA) on bovine polymorphonuclear leukocytes (PMN). Eight healthy, midlactating Holstein cows were used as blood donors. Blood PMN were isolated and incubated with a mixture of NEFA, reflecting composition of bovine plasma NEFA at concentrations that were intended to mimic those found in blood of cows undergoing high, moderate, or low lipomobilization intensity (2, 1, 0.5, 0.25, 0.125, and 0.0625 mM). Control samples were incubated in absence of NEFA. Phagocytosis and oxidative burst activities were assessed by a 2-color flow cytometric method, which was based on oxidation of intracellular dihydrorhodamine 123 to green fluorescent rhodamine 123. Oxidative burst products were generated by incubating PMN with Staphylococcus aureus labeled with propidium iodide. A flow cytometric technique was used to detect PMN viability, necrosis, and apoptosis using fluorescein isothiocyanate-labeled annexin-V and propidium iodide. Phagocytic activity was not affected by NEFA. The highest concentration of NEFA (2 mM) was associated with a dramatic increase of phagocytosis-associated oxidative burst activities with a reduction in cell viability (48.0 vs. 97.5% in control samples) and with a marked increase of necrosis (49.4 vs. 0.5% in control samples). Conversely, the mixture of NEFA did not affect the occurrence of apoptosis. Enhancement of the oxidative burst associated with the highest concentration of NEFA might explain the reduced viability and higher percentage of necrosis observed under the same conditions. This study demonstrated a substantial resistance of bovine PMN to an overload of fatty acids. However, observation that the highest concentration of NEFA regulated some PMN functions encourages the possibility of in vivo studies to assess the relationships between intensity of lipomobilization, plasma NEFA, and bovine PMN functions.

Lymphocyte functions in overconditioned cows around parturition.

The objective of the study was to evaluate the relationships between body condition and lymphocyte functions in periparturient dairy cows. Thirty days before expected calving, 21 Holstein cows were categorized as thin (n = 6), medium (n = 8), or overconditioned (n = 7) based on body condition score (BCS). Blood samples were collected on 21, 14, 7, and 3 d before calving and on d 3, 7, 14, 21, 28, and 35 after parturition. An aliquot of blood was used to determine plasma nonesterified fatty acids (NEFA) and glucose. At 14 and 7 d before, and 14 and 35 d after calving, a second aliquot of blood was used to assess peripheral blood mononuclear cell (PBMC) functions: DNA synthesis, immunoglobulin (Ig) M, and interferon-gamma (IFN-gamma) secretion after mitogen stimulation. During the experiment, all 21 cows showed a decline in BCS. Overconditioned cows lost significantly more BCS than thin cows. After calving, overconditioned cows had higher plasma NEFA compared with thin and medium cows. Conversely, plasma glucose never differed between the 3 categories of cows. Regardless of BCS, DNA synthesis and IgM secretions were significantly lower in PBMC isolated on 7 d before calving compared with those recorded 14 and 35 d after parturition. Conversely, PBMC from the 21 cows did not show any change of IFN-gamma secretion during the experimental period. Taking into consideration the BCS categories, PBMC isolated from overconditioned cows presented lower IgM secretion compared with thin cows on d 14 and 35 after calving. Furthermore, PBMC isolated from overconditioned cows secreted less IFN-gamma compared with thin and medium cows on d 7 before calving. The DNA synthesis of PBMC stimulated with the 3 mitogens did not differ between the 3 categories of cows. In conclusion, immunodepression occurring in cows around calving would be particularly evident in overconditioned cows.

Short communication: effects of nonesterified fatty acids on lymphocyte function in dairy heifers.

This in vitro study was performed to assess the effects of various concentrations of nonesterified fatty acids (NEFA) on lymphocyte function of heifers. Nine Holstein heifers were studied. Peripheral blood mononuclear cells were incubated with various concentrations of NEFA (0, 0.0625, 0.125, 0.25, 0.5, 1, and 2 mmol/L). The mixture of NEFA was represented by C16:0 (30%), C16:1 (5%), C18:0 (15%), C18:1 (45%), and C18:2 (5%). The DNA synthesis was diminished at concentrations of NEFA of 2, 1, and 0.5 mmol/L. The IgM secretion was inhibited at concentrations of NEFA of 2, 1, 0.5, and 0.25 mmol/L. Secretion of IFN-gamma was depressed at concentrations of NEFA of 2, 1, 0.5, 0.25, and 0.125 mmol/L. Increases of plasma NEFA might contribute to explain the higher incidence of infections observed in cows suffering from energy deficit.

[The value of transesophageal echocardiography during cardiac surgery]. / Ruolo dell'ecocardiografia transesofagea durante interventi cardiochirurgici.

The intraoperative use of two-dimensional transesophageal echocardiography has proved effective in the evaluation of left ventricular function after heart operations, in the assessment of adequacy of valve replacement or repair techniques, and in the detection of intracardiac air bubbles before discontinuation of cardiopulmonary bypass. We report here a patient in whom the presence of a tumor mass in the left leaflet of the aortic valve, which was missed at preoperative transthoracic echocardiogram and would have most likely been the cause of systemic embolization, was diagnosed by two-dimensional transesophageal echocardiographic monitoring. We hope that this experience may support the use of two-dimensional transesophageal echocardiography during cardiac surgery.

Multivariate analysis of survival after malfunctioning biological and mechanical prosthesis replacement.

BACKGROUND: Results of valvular reoperations depend on extrinsic and patients' intrinsic risk factors. New prosthetic substitutes continue to appear and the clinical effect is difficult to evaluate. Randomized studies are limited by patient selection and follow-up time. We followed the patient-centric outcome research applied to a large database of valvular operations. METHODS: Between January 1, 1970 and January 1, 1995 755 patients underwent one reoperation, 96 a second reoperation, and 12 a third reoperation. On January 1, 1996 a common closing date follow-up was obtained in 98.7% of reoperated patients. Multivariable analysis in the hazard domain was applied to obtain an upgradable model of survival that could be used for predictions and treatment comparison. RESULTS: Postoperative death hazard showed an early phase merging within 6 months with a constant low hazard phase. The survival proportion was 0.65 (70% CL, 0.63 to 0.67) at 5 years, 0.51 (70% CL, 0.49 to 0.53) at 10 years, 0.47 (range, 0.44 to 0.49) at 15 years, 0.42 (70% CL, 0.39 to 0.46) at 20 and 25 years. Significant incremental risk factors for early mortality were reoperative era 1970 to 1980 (hazard ratio = 2.8), reoperation number (hazard ratio = 1.9), heart penetration on surgery (hazard ratio = 7.6), emergent operation (hazard ratio = 5.8), urgent operation (hazard ratio = 2.1), prosthetic thrombosis (hazard ratio = 2.4), acute prosthetic endocarditis (hazard ratio = 3.0), acute endocarditis of the natural valve at antecedent operation (hazard ratio = 3.2), original floppy valve pathology (hazard ratio = 3.2), and mitroaortic replacement (hazard ratio = 5.7). Isolated mitral reoperation had a lower risk (hazard ratio = 0.5). Significant incremental risk factors for constant phase were: operative era (1970 to 1980) (hazard ratio = 2.0), congestive heart failure (hazard ratio = 2.6), reoperation on tricuspid valve after previous mitral insertion (hazard ratio = 4.9), reoperation for recurring dehiscence (hazard ratio = 4.6), double-valve procedure (hazard ratio = 1.6), coronary artery bypass graft (hazard ratio = 2.7), aortic root disease at original operation (hazard ratio = 2.1), older operative age (hazard ratio = 1.1). Use of bileaflet prosthesis was found to decrease significantly (p = 0.0002) the death risk (hazard ratio = 0.2). CONCLUSIONS: There is no late uprising hazard, and surviving patients remain exposed to a low risk of death (4% of patients per year). Considering simultaneously the confounding from operative age and operative era and the many concomitant risk factors, survival appears favorably influenced by use of bileaflet valves on reoperation.

Aortic dissection type A versus type B: a different post-surgical death hazard?

OBJECTIVE: Patients with type B aortic dissection differ from patients with type A dissection in age, hypertension prevalence, indications and timing of surgical treatment, yet reported long-term results have been rather similar (see Doroghazi et al. J Am Coll Cardiol 1984;3:1026-1034). METHODS: With the aim of comparing the post-surgical history, we have reviewed our results in 288 dissections, 213 type A and 75 type B, operated consecutively between 1 January 1970 and 31 November 1994. Follow-up was 100% complete. Empirical survival of both groups was interpolated with a fully parametric method and the shape and scale of the hazard function was investigated. RESULTS: Survival was not significantly different between type A and type B. Parametric survival was, respectively, 0.52% (70% C.L.: 0.48-0.55) vs. 0.56% (0.51-0.62) at 5 years, 0.44% (0.40-0.47) vs. 0.28% (0.23-0.25) at 10 years, 0.37% (0.33-0.41) vs. 0.25% (0.19-0.32) at 15 years, and 0.31% (0.26-0.35) vs. 0.24% (0.18-0.31) at 20 years. Following the high perioperative risk phase in type A dissection, the intermediate and late risk remains constant at a rate of 0.0033 events/month (3.9% patient-years (pt.-years)). By contrast, the postoperative course of type B dissection shows an intermediate risk phase between 4 and 10 years with an average linearized risk of 9.3% pt.-years and a peak of 20%. This determined lower survival rates (24 vs. 31% at 20 years, P = NS). CONCLUSIONS: We conclude that patients with type B dissection have a steeper postoperative death hazard as compared to type A dissection patients. Age confounding or late entry do not explain the difference. This could be possibly related to a greater propensity for expansion, higher risk of malperfusion complications or to limitations of our current surgical treatment.

Should right-sided fibroelastomas be operated upon?

There is general agreement that left-sided elastomas must be removed to avoid systemic complications. Right-sided localization is less risky and surgical treatment is not agreed upon. We report a case of surgical resected fibroelastoma of the tricuspid valve and discuss the indications to surgery by reviewing the literature on the few reported cases. We feel that, if surgery is timely, the tumor can be resected, thus preserving the native valve. This provides an opportunity to prevent possible right-sided complications due to increasing tumor size and embolization.

Aorto-right atrial fistula: a rare complication of aortic dissection type A. A report of two cases.

BACKGROUND: Aortic dissection with rupture into the right atrium is an extremely rare condition and rapidly lethal. The authors report their experience in the treatment of two complicated aortic dissections observed at 85 and 93 months after previous cardiac operations. These were redo mitral valve replacement and saphenous vein coronary artery bypass grafts. METHODS: Both cases underwent hospital admission on an emergency basis because of severe chest pain and cardiac failure. One case had a history of hypertension. The aortography revealed aortic dissection and a fistulous communication into the right atrium. At surgery dissection repair and closure of the fistula was performed. Furthermore in one case vein grafts were reimplanted into the vascular graft. RESULTS: Both patients survived the operation without complications, were rapidly extubated and were asymptomatic and fully active at late follow-up. CONCLUSIONS: In the light of these results we conclude by affirming that aortic dissection with rupture into the right atrium is an extremely rare condition, rapidly lethal. Patient survival is strictly dependent on the time interval between fistulization of the dissection and the operation.

Aortic dissection in puerperium: a case report.

An acute type A aortic dissection, complicated by massive aortic regurgitation, was diagnosed in the case of a 32-year-old woman, thirty-three days post partum. Emergency operation (Cabrol II) was performed with an uneventful postoperative course. We draw attention to this high risk event, which is particularly apt to involve women within a short time after an otherwise uneventful pregnancy.

Aortic valve prosthesis and late survival of successfully repaired type A dissection.

Seventy-two operative survivors of acute type A dissection between 1973 and 1993 had a complete follow up with a 16 years actuarial survival of 57% and a reoperation free actuarial survival of 34%. Follow up was 100% complete and covered a total of 500.6 patients-years with a median of seven years. Distal tear location (proximal, medium or distal aortic arch) with retrograde dissection toward the aortic valve was the single most important predictor of late mortality with a relative risk of 4.4 (70%CL 2.4-8.2) (p = 0.016). Mortality rate of patients with an aortic valve prosthesis was 6.2%/patient-year vs. 1.7/patient-year without aortic valve prosthesis, with a relative risk of 3.4 (70%CL 2.0-5.8) (p = 0.02). This finding could be due to confounding of variables related both to death and need of aortic valve replacement. Therefore a multivariate proportional hazard analysis, with mandatory inclusion of possible confounders, was done. It showed that patients with aortic valvular prosthesis had eight times higher risk (70% CL 2.7-24.2); prosthetic aortic valves and conservative aortic root procedures had an unconfounded relative risk of 14 times higher (70%CL 3.4-58.7) (P = 0.06), whereas patients with a composite conduit had a six times higher risk (70%CL 2.0-19.9) (p = 0.11). These findings support the attitude favoring a selective approach to aortic root repair and oppose standardized use of aortic valve prosthesis or composite conduit in acute type A dissection.

Long-term results of mitral commissurotomy.

Between January 1968 and December 1989, 280 patients underwent conservative surgical treatment for pure mitral stenosis. Closed commissurotomy was utilized in 134 patients, with a mean age of 38 +/- 11 years and a mean valve area of 1.0 +/- 0.29 cm2. Open commissurotomy was performed in 146 older patients (mean age 44 +/- 11 years) with a mean valve area of 0.9 +/- 0.3 cm2. The perioperative mortality was 3% in closed procedures and 3.4% in open procedures. Surviving patients were evaluated by questionnaires or phone interviews, and 129 patients were examined by two-dimensional echocardiography with the purpose of analyzing long-term results. Follow-up was 95% complete (Grunkemeier-Starr method), with a median of 18 years in patients with closed commissurotomy and 6.6 years in patients with open commissurotomy. The actuarial survival at 21 years was 60.8% (70% confidence limits 55% to 66%) in patients having closed commissurotomies and 60.6% (70% confidence limits 49% to 71%) at 22 years in patients having open commissurotomies. The "effective palliation" rate, defined by clinical and echocardiographic criteria, was 47% at 15 years and 15% at 20 years. We conclude that mitral commissurotomy is the procedure of choice in pure mitral valve stenosis and should be applied early. When performed in patients aged less than 40 years, a 78% (70% confidence limits 72% to 84%) survival at 18 years and 67% "effective palliation" at 15 years were observed. The closed valvotomy results of our study support the present trend toward use of percutaneous balloon valvotomy.

Long-term echocardiographic evaluation of closed and open mitral valvulotomy.

From 1968 to 1989, 280 patients with post-rheumatic pure mitral stenosis underwent surgical commissurotomy; 134 a closed and 146 an open technique. Follow-up exceeded 15 years in 56.7% of the patients. Echocardiographic analysis was performed in 120 patients and disclosed a larger mitral valve area in patients who underwent open valvulotomy (1.9 +/- 0.5 cm2 vs. 1.5 +/- 0.4 cm2 for the closed technique, P < 0.0002). On the other hand, considering the occurrence of post-surgical mitral regurgitation at a level greater than, or equal to moderate, open valvulotomy produced less favorable results (18.5% vs. 5% for the closed technique, P < 0.01).

Does Down syndrome affect prognosis of surgically managed atrioventricular canal defects?

The appropriateness of surgical correction of complete atrioventricular canal defect in patients with Down syndrome has been questioned on a cost-benefit basis. Our experience with nonselective correction of all patients with atrioventricular canal defects gave us the opportunity to evaluate the impact of Down syndrome on postoperative survival. Between January 1, 1975, and December 31, 1989, we operated on 94 patients with Down syndrome and on 127 genetically normal patients. One hundred thirty-four patients had partial or intermediate atrioventricular canal defect (28% Down patients) and 87 had complete atrioventricular canal defect (74% Down patients). Thirty-two patients died perioperatively and 10 patients died during the 15-year follow-up. The actuarial survival was 90% in the genetically normal patients and 57% in patients with Down syndrome (p < 0.0001). Nonetheless, when the confounding effects of pulmonary vascular resistance and the prevalence of more severe anatomic forms in patients with Down syndrome were eliminated with a multivariable analysis in the hazard domain, Down syndrome was not a significant independent incremental risk factor. This was verified by fitting parametric survival to actuarial survival graphically and by a testing of fit. Patients with Down syndrome underwent fewer reoperations and fared as well as or even better, on clinical and echocardiographic investigation, than their genetically normal counterparts.

Successful treatment of a patient after sudden loss of the disc in a Björk-Shiley convexo-concave mitral prosthesis.

The patient's survival after minor strut fracture and migration of a Björk-Shiley mitral prosthetic disc is presented. The operation was carried out in two stages: first emergency replacement of the mitral prosthesis and, later, elective removal of the dislocated disc.

The surgical anatomy of hearts with no direct communication between the right atrium and the ventricular mass--so-called tricuspid atresia.

Seventy-six hearts were studied having no direct communication between the right atrium and the ventricular mass. The different cardiac chamber combinations producing so-called "tricuspid atresia" were considered. The nature of the atrioventricular valve atresia, the morphology of the ventricular mass, the size and position of the interventricular communication, the ventriculoarterial connection, and the presence of subarterial outflow tract obstruction were all analyzed. The majority of cases were of the "classical" type, i.e., absent right atrioventricular connection with the left atrium connected to the left ventricle. In another group there was absence of the right atrioventricular connection but the left atrium drained into the morphologically right ventricle, which was left-sided. In a third group both atrial chambers connected with the ventricular mass but some structure, an imperforate valve or muscular partition, completely blocked the flow pathway through the right side of the heart. All the hearts described are candidates for the Fontan procedure with either an atrioventricular or an atriopulmonary conduit. The surgical options would not be affected by the observed variability at the atrioventricular junction but would be dictated by the feasibility of incorporating the subpulmonary ventricle within the pulmonary circulation.

Palliative surgery for single ventricle heart malformations.

During a 6-year period, 24 patients, aged 7 days to 18 years, underwent palliative surgery for single-ventricle heart malformations; 22 has single-left ventricle with outlet chamber (14 with L-transposition); only two had type C malformation (van Praagh). They were subdivided according to physiology into two groups: the first included 15 patients with decreased pulmonary blood flow, whose main clinical feature was arterial desaturation; the second consisted of nine patients with increased pulmonary blood flow, who presented early with unmanageable heart failure. The first group was treated with a Blalock-Taussig shunt (typical or modified) in 12 cases (one death due to preoperative acute renal failure), with a Waterston or Potts shunt in two cases (both died early postoperatively), and by enlargement of the bulbo-ventricular foramen in one (who died at operation). No late deaths were seen and the clinical status of the survivors is judged optimal. Patients of the second group received a pulmonary artery banding plus a number of associated procedures: coarctation repair (2), ligation of a patent ductus arteriosus (2), Blalock-Hanlon atrial septectomy (1), tricuspid valve replacement (1). There was only one early death due to critical subaortic stenosis produced by a restrictive outlet foramen; however, there were five late deaths and two cases of surgical failure with persistent pulmonary hypertension. An analysis of the best palliative approach in patients with single-ventricle heart malformations is made, based upon the results of this series and taking into consideration the possibility of future intracardiac repair.

[Surgical treatment of infectious endocarditis in the active phase. Experience in 40 cases]. / Trattamento chirurgico dell'endocardite infettiva in fase attiva. Esperienza su 40 casi.

Despite recent advances in antimicrobial therapy infective endocarditis (IE) still remains a major surgical problem. All patients undergoing surgical treatment for IE at our Institution since 1970 were reviewed; among these in 40 IE was considered to be active at time of operation. Thirty patients were males and 10 females, ranging in age from 11 to 66 years (average 41); indications for operation were heart failure in 31, mycotic emboli in 5, and sepsis in 4. Nine were in NYHA functional class 11, 18 in NYHA class III, and 13 in class IV. Aortic valve replacement (AVR) was performed in 24 cases, mitral valve replacement (MVR) in 5 and multiple valve replacement (PVR) in 11. Overall hospital mortality was 15% (4.2% in the AVR group, 40% in the MVR group, and 27% in the PVR group). Postoperative follow-up was available in all survivors. Four patients died in the late postoperative period for not infective causes. Almost long-term survivors show, from 7 months to 10 years (average 58 months) postoperatively, a significant improvement. No complications related to the initial infective process were recorded. According to the results of the present study the following conclusions can be drawn: 1) active IE does not represent a contraindication to open heart surgery and prosthetic valve replacement; 2) the surgical results depend not only on the degree of cardiac failure, but mainly on its duration; 3) early surgical intervention affects favourably the prognosis, especially in cases of isolated aortic valve involvement; 4) the surgical management of IE removes the focus of infection.