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Biomedical subjects

A M Perna

Publications and source records attributed to A M Perna.

At least 37 records · Page 2Linked to original sources
PubMed1996

Ultrastructural evidence of myocardial alterations in the course of heterotopic heart transplantation.

Using a novel model of heterotopic rat heart transplantation, the present study was undertaken to evaluate whether parenchymal and microvascular alterations of the ischemic and reperfused myocardium occurred and could be related to local neutrophil infiltration. In such a model, hearts were rapidly excised from donor rats, maintained in a cold saline solution at 4 degrees C and then reimplanted in recipient animals. Muscle biopsies of the ischemic and reperfused myocardium were analysed by ultrastructural and immunohistochemical techniques. Although the cold storage of the hearts provided a good protection against the ischemic insults, reperfusion with the recipient blood caused severe myocardial cell injury and microvascular damage. In particular, the microvascular endothelium showed numerous discontinuities due to the partial destruction of endothelial cell. The altered endothelial integrity was associated with aggregation and adhesion of platelets to the luminal surface. Contrary to other models of ischemia and reperfusion, where neutrophils are considered the major source of oxygen radicals and cellular dysfunctions at reperfusion, in our samples the burst of these toxic metabolites did not originate from such cells. In fact, no neutrophils were seen to accumulate within the ischemic as well as reperfused myocardium. Accordingly, the microvascular endothelium did not express E-selectin, an adhesive molecule which is responsible for the increased adherence and emigration of neutrophils in the microvasculature.

Animals↗
PubMed1994

Cardiac tamponade secondary to intrapericardial rupture of a hepatic amoebic abscess.

We report the case of a patient who underwent an emergency subxiphoid pericardiectomy with evacuation of 1700 cc of anchovy sauce-like fluid. On pericardial inspection a fistulous communication was seen with a cavity in the left hepatic lobe. No loculi or adhesions were found in the pericardial sac and no further surgical procedure was advised. The hepatic cavity and pericardium were drained: bacteriological investigation of the fluid yielded entamoeba histolytica and chloroquine was administered. Apart from the rarity of the observation in western countries, we discuss surgical approaches in cases of unknown purulent pericardial effusions, stressing the possibility of achieving a good surgical result even with a minor surgical procedure such as subxiphoid pericardiectomy and drainage.

Adult↗
PubMed1992

[Heterotopic heart transplantation in the rat: an experimental method for evaluating myocardial protection].

This research represents the first part of a project finalized to prolong the ischemic time of the explanted heart. Our experimental model utilizes rat hearts heterotopically transplanted into the abdomen of a recipient: a denervated heart but perfused by blood as to permit a good evaluation of the reperfusion damage. We used 3 different types of cardioplegic solutions to achieve cardiac arrest: the first of the intracellular fluid type, the second of the extracellular type and the third one as a standard cardioplegic solution supplemented by Ca++ antagonist. Cold saline 4 degrees C was used as control. Histological patterns, birefringence index and intracellular content of high energy phosphates were evaluated. Specimens were taken after 1 hour of ischemic time and after 1 hour of reperfusion. Early results show that administration of cardioplegic solution maintains birefringence index and preserve high energy phosphates: among the 3 different types of solution the intracellular type seems to achieve better results although the number of experiments is too small to show any statistical significance. These data show that this model is appropriate to test cardioplegic solutions and their effectiveness.

Abdomen↗
PubMed1991

Epidemiological aspects of hepatitis B in Palermo: changes in HBV spread.

Prevalence of HBV infection in Palermo was investigated in 1989, in comparison with similar data observed in 1982. Between September 1988 and April 1989, 1001 serum samples taken from healthy individuals or from patients with pathology unrelated to liver diseases, in the age groups 0 to 59 years, were collected. Prevalence of HBsAg and anti-HBc was, respectively, 2.7% and 24.3% in males, 2.3% and 19% in females. Prevalence was inversely related to socioeconomic level as defined by occupation, educational level and area of residence. Prevalence of HBV markers in 1989 was compared with that of a sample of sera taken in 1982 and stored at -20 degrees C. Prevalence was lower in 1989 for age groups under 20, while no difference was seen in older age groups.

Adolescent↗
PubMed1990

[Mitral valve replacement with the Björk-Shiley monostrut prosthesis: a 4-year clinical experience].

Mitral valve replacement with Björk-Shiley monostrut prostheses was performed in 142 patients, aged 18 to 73 (mean age: 53.8). A group of 101 patients underwent isolated mitral replacement (group A), while both mitral and aortic (in one case tricuspid) valves were replaced in 41 (group B). In 19 of group A patients and in 9 of group B patients a tricuspid annuloplasty was added. Hospital mortality was one case in each group (group A: 1%; group B:2.4%). The cause of death was low output in both cases (i.e. not valve-related). Late mortality occurred in 4 cases (4%) in group A, and in 3 cases (7.3%) in group B (follow-up: 6 to 58 months; mean follow-up: 24 months). Actuarial survival was 93.79% in group A and 89.94% in group B one year after surgery; it was 93.79% in group A and 81.76% in group B after 3 years. All deaths from undetermined causes, as well as any new unexplained neurological deficit or peripheral emboli, were considered to be valve-related: 84.18% of group A patients, as well as 67.90% of group B, were event free after 3 year (actuarial). most valve-related events occurred in the first year after surgery. We observed thromboembolism in 3 cases for each group: one patient in group B had pannus formation over the prosthetic annulus; prosthetic valve endocarditis in 1 case of group A and 2 of group B; significant hemorrhage due to anticoagulant therapy in 1 (group A); one patient in each group died suddenly, 4 and 7 months postoperatively. One group A patient and 2 group B patients were reoperated: a new valve prosthesis was implanted in two patients. Mean transvalvular gradient, as determined by echocardiography, was 3.8 +/- 2.3 (SD) mmHg in the case of isolated mitral replacement. In conclusion, we believe these results are highly encouraging, especially in the isolated mitral replacement group. Björk-Shiley monostrut prosthesis has been demonstrated to be a reliable valve substitute, with an acceptable incidence of complications. No Björk-Shiley monostrut prosthesis structural deterioration was seen, and its hemodynamic behaviour may be considered satisfactory.

Actuarial Analysis↗
PubMed1989

High-dose aprotinin: hemostatic effects in open heart operations.

Two groups of patients were prospectively studied to evaluate the hemostatic effects of high-dose aprotinin in open heart operations. Group A patients (n = 22) received aprotinin during the entire surgical procedure. Group B patients (n = 12) served as controls. The groups were homogeneous for base variables and for cardiopulmonary bypass duration. Postoperative bleeding was lower in group A (mean, 486 mL) than in group B (830 mL) (p less than 0.01). The need for banked blood decreased by approximately half in the aprotinin patients (mean: group A, 213 mL; group B, 409 mL). Hemoglobin levels were similar in the two groups (postoperative day 7: group A, 11.29 g/100 mL; group B, 11.26 g/100 mL; NS). Platelet count decreased at the end of operation in both groups (99,000 and 95,000/mL, respectively; NS) and then increased beyond baseline levels before discharge. No complications were observed that could be attributed to aprotinin. In conclusion, we believe that the use of high-dose aprotinin is safe and effective. It decreases blood loss and reduces the need for banked blood in cardiac operations, particularly in select groups of patients (eg, those undergoing reoperation, Jehovah's Witnesses, those with renal failure).

Adult↗
PubMed1989

Epidemiology of boutonneuse fever in western Sicily: demonstration of multiple spotted fever group-Rickettsiae subtypes.

Electrophoretic analysis of the proteins and genomic DNA of spotted fever-group Rickettsiae isolated from ticks and a human in Western Sicily show that at least two distinct subtypes other than R. conorii are present in this region. All of the spotted fever-group isolates share common features with other, well-defined spotted fever-group rickettsial species, e.g. R. sibirica, Thai Tick Typhus, and R. rickettsii. Based on these data, caution is recommended when identifying species by the more traditional and less specific tests. Studies of the ecology and epidemiology of spotted fever-group Rickettsiae in regions where R. conorii infections occur would benefit and be challenged by intensive antigenic analyses of the proteins and genomic DNA of the various strains of the spotted fever-group Rickettsiae present in those areas.

Animals↗
PubMed1988

[Compliance problems in the oral anticoagulant treatment of patients wearing heart valve prostheses].

The need for and the efficacy of oral anticoagulation in patients who have undergone prosthetic valve replacement is widely demonstrated. The aim of this study is to assess how dicumarolic treatment is understood and actually accomplished by patients. A 30-question form was sent to 292 patients discharged following valve replacement, 5 to 45 months (mean: 19 months) after surgery. All of the 220 patients who submitted their answers, were effectively on oral anticoagulants. More than 95% of them knew exactly the suggested optimal prothrombin activity range. About one fifth of the patients has laboratory tests performed weekly, and nearly one half does so every 10-15 days. One fourth of the patients does not consult a physician for decision making about drug dosage. Difficulties in maintaining anticoagulation in the desired range, occurring at least once every month, are reported by 18.6% of patients. Haemorrhage was never experienced by 83.18%; in one single case thromboembolism was apparent. A few patients (2.27%) think of oral anticoagulation as a "difficult" treatment. We conclude that complete information is needed, about the aim, the modality, and the potential hazard of oral anticoagulation, so that a better understanding of the treatment and an improved cooperation between physicians and patients can result in benefits, in terms of the safety and efficacy of life-long antithrombotic therapy.

Administration, Oral↗
PubMed1987

Intermittent reperfusion extends myocardial preservation for transplantation.

A protocol was developed to compare prolonged heart preservation by hypothermic storage with prolonged hypothermic storage interrupted by a period of reperfusion. Hearts from adult mongrel dogs were excised after administration of 4 degrees C crystalloid cardioplegia. Group A hearts (N = 7) underwent 7.5 hours of ischemia at 4 degrees C followed by 1.5 hours of reperfusion and rewarming (A0). Group B hearts (N = 8) underwent 3 hours of ischemia at 4 degrees C, 1.5 hours of reperfusion and rewarming (B1), 3 additional hours of ischemia at 4 degrees C following repeat cardioplegia, and finally 1.5 hours of reperfusion and rewarming (B2). During reperfusion, hearts were defibrillated and left ventricular (LV) function was assessed by measuring isovolumic peak systolic pressure and maximum positive rate of rise of LV pressure (+dP/dtmax) with an intraventricular balloon. LV biopsy samples for adenosine triphosphate (ATP) assay were obtained before ischemia and after each rewarming period. One Group A heart could not be defibrillated and studied. All Group B hearts completed the protocol. LV function, as assessed by peak pressure and +dP/dtmax, at B1 and B2 exceeded values obtained at A0, but the differences were not statistically significant. The mean ATP level was 63.4 +/- 7.7% of baseline at B1 and 79.7 +/- 4.3% of baseline at B2 (p less than .03). The mean ATP level was 57.9 +/- 5.9% of baseline at A0 (p less than .007, B2 vs. A0). It is presumed that intermittent reperfusion allows repletion of substrate stores, which results in improved myocardial protection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1986

Isolation on "VERO" cells of a spotted fever group rickettsia "Mortilli strain" from Rhipicephalus sanguineus.

The isolation of a Spotted Fever Group (SFG) Rickettsia "Mortilli strain" from brown dog ticks Rhipicephalus sanguineus removed from dogs associated with a confirmed case of Boutonneuse Fever (BF) in a site of a Western Sicily is reported. The need is stressed for isolation and adaption on cell cultures of SFG rickettsial strains for analysis of antigenic structure employing modern methodology.

Animals↗
PubMed1986

Epidemiology of boutonneuse fever in western Sicily. Distribution and prevalence of spotted fever group rickettsial infection in dog ticks (Rhipicephalus sanguineus).

The distribution and prevalence of spotted fever group rickettsial infection in the ixodid dog tick Rhipicephalus sanguineus were found to occur at a rate of 19.7% with variation related to geographic and sociooccupational factors. A higher rate of infection was demonstrated in ticks removed from dogs associated with documented cases of boutonneuse fever. The results fit into available clinical and seroepidemiologic data on Rickettsia conorii infection in western Sicily.

Animals↗