Search PubMed⌕ Search

Biomedical subjects

A F Rossi

Publications and source records attributed to A F Rossi.

32 records · Page 2Linked to original sources
PubMed1994

Usefulness of intermittent monitoring of mixed venous oxygen saturation after stage I palliation for hypoplastic left heart syndrome.

Most deaths after stage I palliation for hypoplastic left heart syndrome have occurred within the first 24 hours after surgery. Efforts to improve 1-day survival should therefore have significant impact on improving overall survival. Early death has most often been attributed to low cardiac output and abnormalities of pulmonary to systemic flow ratio (Qp/Qs). Thirteen infants underwent stage I palliation and had a catheter inserted in the high superior vena cava (SVC) for intermittent measurement of SVC oxygen saturation. Calculation of Qp/Qs was achieved using SVC saturation as a mixed venous oxygen saturation, and estimating pulmonary venous oxygen saturation. Eleven patients survived, and 2 patients died within the first 24 hours. Abnormalities in Qp/Qs were noted in 12 of 13 patients after operation. In 10 of these 12 patients, there was a high Qp/Qs, which has been associated with poor outcome. High Qp/Qs was noted even in patients with acceptable arterial oxygen saturations (< 85%). SVC saturation increased in all survivors during the first 24 hours, and was associated with a decrease in Qp/Qs. Measurement of SVC oxygen saturation appears to be a valuable adjuvant in the postoperative management of infants after stage I palliation of hypoplastic left heart syndrome. Major abnormalities in Qp/Qs can be detected even with acceptable arterial saturations. With this information, early ventilator/pharmaceutical adjustments can be made which may improve stage I survival.

Arteries↗
PubMed1993

Depth in anticorrelated stereograms: effects of spatial density and interocular delay.

Disparity-based depth is not perceived in densely textured, anticorrelated random-dot stereograms (RDSs) whose elements carry opposite signs of brightness contrast on corresponding loci, as extant data show. We observed global depth in anticorrelated RDSs flashed repetitively with an interocular delay. During the delay time, a dot array in one eye was paired with a gray frame in the other eye and thus could interact with the negative afterimage of the contralateral dot array. A correlated RDS (e.g. 8 min arc dots, 50% density, 15-msec flash duration) lost depth with delays > 45 msec. An anticorrelated RDS, that was otherwise identical, showed robust depth when flashed with an interocular delay of some 60 msec. A delay was not always necessary to produce depth. At low dot density (1-2%), anticorrelated RDSs showed disparity-dependent local depth even when displayed continuously, or flashed simultaneously; as dot density alone was increased, depth was progressively lost. To make global depth visible in a dense RDS flashed with an interocular delay, the internal response had to be strongly biphasic. Our results support the generally held notion that cyclopean depth signals emerge exclusively from same-sign binocular cortical filters. However, the exclusionary rule may be invalid with respect to the processing of coarse local depth with figural stimuli. Relative depth between a pair of small dots was easily perceived when one of the dots was in opposite contrast, but the depth threshold was then about 0.5 log unit higher than with the same-contrast pair of dots indicating that the internal effects of contrast have not all lost their sign prior to binocular disparity processing. It remains to be determined whether depth can be perceived from edges of opposite contrast.

Afterimage↗
PubMed1993

Effects of dietary boron supplementation on broilers.

Two experiments were conducted with a total of 432 broiler chicks to investigate the influence of supplementing different amounts of boron to practical corn-soybean meal diets. The birds were housed in batteries and had free access to feed and water. In Experiment 1, 144 1-day-old broiler chicks were fed a basal diet supplemented with 0, 5, 40, 80, or 120 ppm boron for 21 days. Female body weight was not influenced by the dietary treatments. However, males supplemented with 5 ppm boron were heavier and their tibias resisted more load than the control birds. Overall feed conversion was not influenced by boron. In Experiment 2, 288 1-day-old broiler chicks were fed a basal diet supplemented with 0, 60, 120, 240, or 300 ppm boron for 22 days. Male and female body weights of the 300-ppm group were lower than those of the control birds. Percentage tibia ash was highest with 300 ppm boron. No significant differences were found in intestinal tract weight (grams of intestine per 100 g body weight) among treatments. Boron concentration in the breast muscle and liver increased as dietary concentration of boron increased. Data collected in these two experiments indicated that consumption of diets containing up to 240 ppm boron from hatch to 21 days of age was not detrimental to broiler performance. Data were not conclusive on the need for supplemental boron in broiler diets based on corn and soybean meal.

Animals↗
PubMed1992

Use of adenosine in the management of perioperative arrhythmias in the pediatric cardiac intensive care unit.

OBJECTIVE: To assess the safety, efficacy, and diagnostic usefulness of iv adenosine in treating acute episodes of paroxysmal supraventricular tachycardia in critically ill infants and children with congenital heart disease. DESIGN: A consecutive sample study over a 1-yr period. SETTING: A six-bed pediatric cardiac ICU at a tertiary care center. PATIENTS: Nine consecutive critically ill infants and children with congenital heart disease, either awaiting emergent surgery or in the immediate postoperative period, who had at least one episode of tachyarrhythmia treated with iv adenosine. INTERVENTIONS: In children less than 50 kg, adenosine was administered in incremental doses of 100, 200, and 300 micrograms/kg every 3 mins. Patients weighing greater than 50 kg were given doses of 6, 12, and 18 mg iv. The adenosine protocol was stopped when the arrhythmia was terminated or a mechanism of the arrhythmia was shown that would not respond to adenosine administration. MEASUREMENTS AND MAIN RESULTS: Adenosine was used 14 times in nine patients, all of whom were hemodynamically unstable before or after the development of the tachyarrhythmia. Adenosine was effective in rapidly terminating all nine episodes of paroxysmal supraventricular tachycardia, six of which occurred in patients known to have Wolff-Parkinson-White syndrome. All patients had marked hemodynamic improvement after conversion to normal sinus rhythm. In five episodes of tachyarrhythmia that did not respond to adenosine, the transient block at the atrioventricular (A-V) node helped determine the underlying arrhythmia without clinically important side-effects. CONCLUSIONS: Adenosine can be used safely and effectively in critically ill infants and children with congenital heart disease and perioperative tachyarrhythmia. More investigation into the "chemical conversion" of paroxysmal supraventricular tachycardias as well as its diagnostic value in this subset of critically ill patients is warranted.

Adenosine↗
PubMed1992

Subclinical infectious bursal disease in an integrated broiler production operation.

A field study was designed to determine the prevalence of subclinical infectious bursal disease (IBD) in broiler chickens from a commercial poultry company. Bursae of Fabricius (BF) from two vaccinated and three nonvaccinated broiler flocks were evaluated histologically, and antibody profiles of these broiler and matched parent breeder flocks were established. Lesions of IBD, including lymphoid necrosis, stromal edema, and infiltrates of heterophils and macrophages, were first detected in BF at 24 days of age in both vaccinated and nonvaccinated chickens. At 41 days, all BF had lesions characteristic of IBD, including severe lymphoid depletion, proliferation of epithelial cells, and mild fibroplasia. Although mean maternal antibody levels (measured by enzyme-linked immunosorbent assay) in broilers were apparently protective through day 12, IBD antibodies decreased to nonprotective levels (below 1,000) by day 16 or 20. Titers began to increase by day 28 or 32 because of field exposure. Sentinel birds, placed with broiler flocks, also developed IBD antibody titers. Broiler breeders had low and nonuniform antibody titers. Prevalence of field IBD exposure was high, and existing vaccination programs were not effective.

Animals↗
PubMed1990

Influence of aluminum on phosphorus availability in laying hen diets.

An experiment was conducted to determine the influence of Al on P utilization, as well as to determine the short-term response of laying hens to diets containing different levels of P not bound by A1 (PNB). One hundred and sixty Single Comb White Leghorn hens were assigned to eight treatment diets derived from a 2 by 4 factorial design. Diets varying in two percentages of total P (.5 and 1.0%) and four percentages of Al supplementation (.6, .4, .2, and 0%) from aluminum acetate were fed for 15 days. The calculated PNB for the eight treatments were .03, .18, .33, .48, .53, .68, .83, and .98%, respectively. Egg production and feed intake were significantly lower at the two lowest percentages of PNB (.03 and .18%). At the lowest PNB level (.03%), no eggs were laid during the last 2 days of the experiment by any of the 20 hens fed this diet. Plasma inorganic P was significantly decreased by either lowering the total P of the diet or by increasing the Al. These detrimental effects of Al supplementation were completely reversed by increasing the level of P in the diet. Therefore, the detrimental effects of Al are not due to Al per se, but rather are due indirectly through diminishing P availability. Decreased egg specific gravity caused by high percentages of P was reversed by Al supplementation. As the amount of PNB increased, feed consumption also increased. Maximum feed efficiency and egg production were achieved with PNB values between .33 and .98%.

Aluminum↗
PubMed1982

[Latent neuropathy in rheumatoid arthritis. Electrophysiological study of 45 cases].

Thirty (88.2%) of thirty four patients with rheumatoid arthritis showed evidence of latent neuropathy, as judged by the following tests: measurements of motor and sensory conduction velocity; analysis of single motor units at various sites and under different conditions. All patients demonstrating electrophysiological signs of involvement of nervous functions showed no clinical signs of peripheral neuropathy. On the basis of the present results it is proposed that neurophysiological alterations could depend on a widespread (immunologically mediated?) injury of the axonic membrane.

Adult↗
PubMed1980

Activation of the coagulation system in connective tissue diseases. A study of [125I] fibrinogen clearance.

Fifty-one patients with different connective tissue diseases in either active or clinically inactive phase were studied to detect the incidence of chronic or subclinical consumption coagulopathy in these forms. Every patient received intravenously 20 mu Ci of [125I] fibrinogen and the clearance of the labeled fibrinogen was evaluated and expressed by the T/2 method. The data confirm the activation of the coagulation system in connective tissue diseases. In patients with S.L.E., enhanced fibrinogen consumption was significantly correlated with disease activity, DNA-binding activity test, serum complement level and an aspecific inflammatory index (serum mucoprotein level). These preliminary data suggest the usefulness of complementary treatment in connective tissue diseases to counteract this specific pathogenetic mechanism.

Complement System Proteins↗
PubMedDate not supplied

Malignant wide complex tachycardia after adenosine administration to a postoperative pediatric patient with congenital heart disease.

Adenosine has become the treatment of choice for paroxysmal supraventricular tachycardia because of its safety and efficacy. There have been no reports of malignant arrhythmias occurring after adenosine administration. This case report presents the occurrence of a malignant wide complex tachycardia after intravenous adenosine administration in a 10-year-old boy 2 days after a Fontan procedure. Thus the administration of adenosine in a critically ill postoperative patient can have morbidity or potential mortality and must be monitored closely.

Adenosine↗