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Biomedical subjects

F Castaldo

Publications and source records attributed to F Castaldo.

At least 19 recordsLinked to original sources
PubMed1995

Low-field magnetic resonance imaging in the evaluation of mechanical and biological heart valve function.

Magnetic resonance imaging (MRI) has been frequently considered unsafe for patients with ferromagnetic implants: risks to be considered include induction of electric current, heating and dislocation of the prosthesis. Previous in vitro and in vivo studies have indicated the possibility of performing MRI examinations on patients with prosthetic heart valves. The aim of our study was to verify the presence of artifacts at the level of the prosthetic heart valve in vivo using a low-field MR unit (0.2 T) and to define the possibility of a functional analysis of the valve in patients with biomedical or mechanical prostheses. We evaluated 14 patients surgically treated for implantation of nine biological and seven mechanical aortic and mitral valves. A low-field MR unit (0.2 T) was employed using cine-MR technique on long- and short-axis view. The images were acquired on planes parallel and perpendicular to the valvular plane. Semiquantitative analysis with double-blind evaluation for definition of the extent of the artifact was performed. Three classes of artifacts were distinguished from minimal to significant. The examinations showed the presence of minimal artifacts in all biological heart valves and moderate artifacts in mechanical valves giving good qualitative data on blood flow near the valve. Analysis of the flow behind the valve showed signs of normal function in 13 prostheses and pathological findings in the remaining three. In these latter cases, MRI was able to define the presence of a pathologic aortic pressure gradient, mitral insufficiency and malpositioning of the mitral valve causing subvalvular turbulence. Nevertheless, we believe that the application of velocity-encoding cine-MR is more promising than semiquantitative analysis of artifacts.

Adult↗
PubMed1995

[Struma cordis: right intraventricular ectopic thyroid].

The authors report the case of a benign tumour composed of hyperplasic thyroid tissue in the right ventricle, diagnosed in a 43 year old woman by echocardiography after a syncopal episode. The outcome was favourable with a 13 year follow-up after surgery.

Adult↗
PubMed1993

[Phosphocalcium metabolism in patients with calcified valvular bioprosthesis].

Calcium and gla-protein content are increased in the calcifications of cardiac bioprostheses. Such calcifications are more frequent during growth, pregnancy and renal failure when bone gla-protein levels are elevated. We investigated whether bone gla-protein and other markers of calcium metabolism play a role in bioprostheses calcifications. Forty-seven patients were separated into 2 groups according to the presence (group A, n = 9) or absence (group B, n = 38) of bioprostheses calcifications, as assessed by echo-doppler and surgery. Plasma levels of calcium, phosphorus, magnesium, creatinine and alkaline phosphatases were measured by standard laboratory methods, parathormone and those of bone gla-protein by specific radioimmunoassays. Results (mean +/- SEM) were compared (group A versus group B, P < 0.01) using Student's test and one-factor variance analysis (ANOVA). Age was similar in both group (53 +/- 12.9 vs 50 +/- 12.3 yrs), whereas duration of implant was greater in group A (104 +/- 12.4 vs 66 +/- 6.5 months, P < 0.01). No statistically significant difference was found between group A and B concerning biochemical and/or hormonal markers of calcium metabolism. These negative results merit to be discussed, and further studies will be needed to explore the potential role of circulating bone gla-protein in bioprostheses calcifications.

Aortic Valve↗
PubMed1993

[Ultrasonographic and urodynamic evaluation in stress incontinence].

Transvaginal sonography can show partial urinary penetration in the urethra in patients with no clinical incontinence. The Fluid Bridge Test-Pressure urodynamically demonstrates the same phenomenon. We compared these two technics in women with stress urinary incontinence (SUI). 49 patients underwent urodynamic testing and transvaginal sonography; 18 had SUI, 20 were asymptomatic postoperatively (Burch procedure) and 11 were normal controls. Urodynamics consisted of filling cystometry with saline (infusion speed: ml 70/min) using transurethral Foley catheter (n degree 14 Fr), and a profilometric-pressure Bard catheter (10 Fr); micturitional cystometry; uroflowmetry; clino- and orthostatic urethral pressure profile (UPP) (extraction speed: cm 0.5-1/sec; infusion speed: cm 1.2/min); sphincteric electromyography (EMG); FBT-P with the Bard catheter only. During extraction patients were requested to cough (stress condition). If the urethra is incompetent pressure is transmitted to the water column connected to the pressure transducer, and a "spike" is observed. A competent urethra shows little pressure variation. Ultrasound (US) equipment consisted in a General Electric (RT 3600) sonograph with an electronic transvaginal probe (7.5 MHz) inserted in a gel-lubricated condom. The probe was positioned in the vaginal vestibule in direct proximity to the urethra. Axial and coronal scannings were performed. Echo-imagings were submitted to "post-processing" on US recording equipment. Fluid penetration in the urethra was evident if iperchogenic "turbulence" was observed on playback of the dynamic sonogram on a videocassette recorder (VCR) connected to the sonograph. The SUI group shows leakage of water under stress without detrusorial activity and dynamic UPP with reduced transmission of abdominal pressure on the urethra.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromyography↗
PubMed1993

[Comparison of methods for the diagnosis of urinary obstruction in women].

The International Continence Society does not offer secure guidelines for the diagnosis of micturitional obstruction. The problem has been extensively addressed in relation to male voiding difficulties. Little is known on the subject in female patients. Two criteria for the diagnosis of obstructed micturition are in clinical use. The Sussett formula divides the maximum micturitional pressure by the square of the corresponding maximum urinary flow rate. Two cutoffs, corresponding approximately to the 90th and 95th centiles can be used (0.15, and 0.5). A more complex graphic nomogram developed by Schafer plots maximum flow versus maximum detrusor pressure, identifying obstruction and detrusor dysfunction simultaneously according to the author. We feel that these methods, extensively tested on a male population, can both be used on a female population. We noticed that in some instances the results were different. 469 women referred for micturitional disturbances underwent pressure/flow studies. 62 (13.2%) were obstructed according to the Schafer nomogram, 103 (21.9%) and 31 (6.6%) respectively using the Sussett mathematical formula using two different cutoffs (0.15 and 0.5). The two methods identify the same patients only if micturitional pressures are normal (40 to 60 cmH2O) to high (over 60 cmH2O) and the Sussett formula is used with a higher (95th centile) cutoff. This means that both methods are clearly insufficient in the diagnosis of obstruction if detrusor function is impaired. This can happen in case of chronic retention due to detrusor failure after a long-standing obstruction or for primary failures due to central nervous system lesions. Extreme care should be exercised if pressure-flow studies indicate obstruction at low micturitional pressures.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1993

[Acute urinary obstruction in pregnancy].

Five cases of acute urinary obstruction during pregnancy are presented. A complete urodynamic workup, including pressure-flow studies showed high micturitional pressures with little or no flow, with at least 60% residual urine. Filling cystometry, urethral profilometry (static and dynamic), pelvic electromyography were normal. Two cases were due to uterine pelvic incarceration. One of these cases happened very early during pregnancy, because of extensive fibroids. Any cause of abnormal uterine enlargement can lead to early obstruction. Three cases were associated with paraurethral abscess (skenitis in 2 cases, urethral diverticulum in 1). Manual reduction in case of pelvic incarceration or surgical draining and antibiotic therapy in case of abscess were effective in all cases. Immediate catheterization is possible and indicated as soon as urinary obstruction is diagnosed. This prevents neuromuscular dysfunction due to excessive bladder distention. The transurethral catheter might work as a stent, and periurethral surgical drainage is probably safer with a catheter in place. Suprapubic catheterization is probably less useful in this respect. An indwelling catheter removes any urgency in treatment. Voiding difficulties can persist for some days after surgical treatment. Urodynamic testing performed in all indicated acute micturitional obstruction. Anyway, it added little to the clinical understanding of the problem, which was obvious, and the Authors feel that extensive urodynamic testing should be limited to cases presenting with a complex preexisting dysfunction or performed after treatment if symptoms do not disappear completely. All clinically doubtful cases should likewise be investigated. If periurethral abscess or incarceration are evident, simple evaluation of residual urine percentage should be sufficient in establishing the diagnosis.

Acute Disease↗
PubMed1992

[Left coronaro-ventricular fistula after septal myectomy].

The authors report the case of a 17 year old patient operated for valvular aortic stenosis associated with severe hypertrophy of the interventricular septum. The operation consisted of aortic valve replacement and septal myectomy. Color-flow imaging in the postoperative period showed a coronary artery--left ventricular fistula in the region of the septal myectomy. In view of the small size of the fistula on echocardiographic examination and the absence of a codified strategy of management of acquired coronary left ventricular fistula after surgery, a simple Doppler echocardiographic follow-up was proposed in this case.

Adolescent↗
PubMed1988

Clinical comparison of mitral valve replacement using porcine, Starr, and Bjork valves.

The choice of a cardiac prosthesis for mitral valve replacement remains controversial, and thromboembolic complications are still a major cause of morbidity and mortality in patients with mechanical valves. Because of this, permanent anticoagulation with its risks and constraints on daily life is necessary. Bioprostheses, however, are associated with a lower rate of thromboembolic events. Therefore, the need for long-term anticoagulation is minimized. These advantages are counterbalanced by the limited durability of tissue valves. In an effort to give some perspective to this balance, we compared the long-term results of three commonly used mitral valve prostheses. Three hundred patients operated on in the same institution January 1974 to December 1978 form the basis of this evaluation.

Adolescent↗
PubMed1980

Water and ion metabolism in placenta (III). Net movement of water, monovalent and divalent cations in slices from rabbit placenta, at different periods of gestation, incubated under metabolically favorable conditions.

Rabbit placenta slices incubated at 38 degrees C in oxygenated medium, in the presence of endogenous substrates +5 mM glucose, after a period of preincubation of 120 min at 0--1 degrees C, show a net accumulation of potassium and extrusion of water, sodium and calcium. The movement of potassium, sodium and calcium appears to be related to the rate of oxygen consumption of the slices and to be inversely proportional to the age of the tissue. The efficiency of cations movement is also dependent on the nature and composition of the incubation medium. In this respect the potassium concentration of the medium plays a major role. The movement of water, on the other hand, seems to be completely independent from both the rate of respiration and the age of the tissue. The results are discussed in terms of relation between placenta age and senescence, and efficiency of the mechanisms devoted to the cell regulation of water and ions content.

Animals↗
PubMed1979

Water and ion metabolism in placenta. II. Water compartments and electrolytes in slices of rabbit placenta, at different periods of gestation, incubated at 0-1 degree C.

The movement and the distribution of water, sodium, potassium, chloride, magnesium and calcium have been studied in slices prepared from rabbit placentae at different periods of gestation, incubated in condition of depressed metabolism (0-1 degree C). In these conditions the tissue takes up water from the external medium up to a maximum of about 2.0 kg/kg d. wt., which represents 30 per cent of the initial H2O content of the fresh tissue. The extracellular compartment swells progressively and proportionally to the age of the placenta. The sodium and chloride content of the tissue increases while that of potassium decreases and their intracellular concentration reaches, after 120 min, that of the external medium. Magnesium does not show appreciable changes and calcium, too, despite its extreme variability, does not seem to undergo significant variations during the cold incubation. The results obtained show that placenta, like most of other mammalian cell systems, possesses specific metabolism-dependent mechanisms responsible for the maintenance of water distribution and ion gradients among the different tissue compartments. The characteristics and the regulation of these mechanisms are discussed in detail.

Animals↗
PubMed1977

The behaviour of microsomal mono-electron carriers in adult and fetal liver and in placenta throughout pregnancy.

The activities and contents of microsomal mono-electron carriers (NADPH-cytochrome c reductase, NADH-cytochrome b5 reductase, cytochrome P-450 and cytochrome b5) in the liver of 160 pregnant rabbits and their response to phenobarbital (PB) administration were found to be different to that of non pregnant animals and to vary depending on the period of gestation. In fetal liver and in placenta the activities and contents of mixed function oxidase system enzymes are very low and increase from the mid-gestation up to the term of pregnancy. PB has either effect or decreases the enzyme levels. The variations of enzyme content and activity in maternal liver and the different response to PB are related to the hormonal modifications of pregnancy. The behaviour of mono-electron carriers in fetal liver can be related to the process of maturation of this organ. The effect of PB can be due to the interference of the drug with steroid metabolism. The behaviour of mixed function oxidase system enzymes in placenta can be related to the processes of maturation and ageing of organ.

Animals↗
PubMed1977

Water and ion metabolism in placenta. I. water and ion content of rabbit placenta in different periods of gestation.

Total tissue water of rabbit plancenta decreases by 18% between the 9th day and the end of gestation. In the same period intracellular water decreases by 40% and the extracellular compartment swells. Total tissue sodium and chloride content increase by 34% and 27% respectively from the 16th to the 33rd day while potassium decreases by 30%. The intracellular concentration of these ions does not vary greatly during gestation. Moreover the total tissue magnesium content decreases by about 23% at the end of gestation while its intracellular concentration does not show marked changes. Calcium content of rabbit placenta substantially increases during gestation and intracellular calcium shows a fivefold increase from the 16th to the 33rd day of gestation. The results are discussed in terms of relation between water and ion content and placental tissue growth and aging.

Animals↗
PubMed1976

The behaviour of microsomal mono-electron carriers in human placenta during late pregnancy.

The activities and the content of enzymes involved in mixed function oxidase systems (cytochromes P-450 and b5, NADPH-cytochrome c reductase and NADH cytochrome b5 reductase) in microsomes from 114 human placentae were found to increase from the 34th up to the 38th-39th week of gestation and later to decrease until the 43rd week. Such a process can be related to the following: (i) the phospholipid content of microsomal membranes; (ii) the protein synthesis possibly induced by steroids such as androstenedione and testosterone.

Biological Transport↗