Biomedical subjects
Publications and source records attributed to R Bianco.
Perfusion of Rat liver with an oxyphoretic emulsion containing a mixture of perfluorodecalin and N,N-perfluorodiethylcyclohexylamine provides a good oxygenation of the tissue. During perfusion hepatocytes take up some emulsion micelles and this uptake markedly increases when tissue perfusion is suboptimal.
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The physical and mechanical effects of injecting crystalloid cardioplegic solution under various pressures and flows was studied (in canine hearts) to establish a safe method for administering it in the presence of normal coronary arteries. A constant pressure system (300 mm Hg = 15 psi) was maintained in the solution reservoir, and flows and pressures were varied with the use of cannulas of different inner diameters: 0.8, 1.35, 1.6, 2.3, 2.58, and 2.80 mm. Cardioplegia distribution was measured by 15 microns radioactive microspheres. Peak flow rate, total flow, and mean flow rate per infusion were measured by an inline electromagnetic flowmeter probe. Direct aortic root pressure, time to standstill, and myocardial temperatures were recorded by continuous monitoring. Cardiac isoenzymes were measured in the coronary sinus, peripheral blood, and directly in the myocardial tissue. Histologic changes in the left ventricle were examined by light microscopy. The results showed that the higher the flow and pressure, the shorter the prearrest period, the better the flow distribution, and the faster the myocardial temperature drop. Mean aortic root pressures higher than 110 mm Hg and peak flow rates greater than 1500 ml/min caused a higher incidence of mechanical-physical trauma to the vascular endothelium and the endocardium, but cellular protection was good. Low pressure (less than 30 mm Hg) and peak flows (less than 125 ml/min) showed a higher incidence of cellular (myocardial) ischemia, focal necrosis, and uneven flow distribution. An aortic root pressure of 61 +/- 5 mm Hg, a mean peak flow rate of 622 +/- 52 ml/min, and a total flow of 600 ml for the first injection seem to offer the best cellular protection with minimal physical injury to the endothelium and endocardium for a mean canine heart weight of 236 gm.
To investigate the fate of cryopreserved pulmonary conduit allografts, an experimental model was used in lambs. The lambs underwent resection of the pulmonary trunk and valve to the level of the bifurcation of the pulmonary arteries and then were replaced by cryopreserved (CryoLife, Incorporated, Laboratories) pulmonary conduit allografts obtained from lambs of similar size. Lambs were operated on at 4 weeks of age and followed up with cardiac catheterization and cineangiography every 3 months for a period of 18 months. Lambs were electively sacrificed in the following order: two at 1 month, two at 3 months, one at 6 months, two at 12 months, and five at 18 months. To assess the structure of the conduit tissue, sections for light microscopy were obtained from the proximal, midportion, and distal ends of the conduit. While the lambs grew from a weight of 11.7 kg at the time of implant to more than 70 kg at 18 months, the diameter of the pulmonary conduit distended from 16 mm at the time of implant to 17.7, 19.1, 24.9, 34.3, and 33.7 mm at 1, 3, 6, 12, and 18 months, respectively. The length of the conduit also extended from an original inner length of 25 mm and an original outer length of 32 mm to the following dimensions: inner lengths of 27.9, 32.7, 38.8, 43.6, and 45.3 mm, respectively, at 1, 3, 6, 12, and 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)
We consider the approach through the left external jugular vein v/s right external jugular vein (Heinbach-Ivey technique) for the placement of central venous catheters (Broviac Hickman type and others) in pediatric patients. Between January '84 and February '87, 65 central venous catheters were inserted using the Heinbach Ivey technique. In 24.6% of the cases we failed and had to place the catheter through the right internal jugular vein. Between March '87 and November '88, 72 catheters were inserted through the left external jugular vein, only 5 through the left internal jugular vein, with a failure rate of 6%. Our data show that a more favourable anatomy makes easier and quicker the correct placement of a central venous catheter through a left external jugular vein approach.
Despite technical advances in management, the complication of late stricture formation and biliary sepsis still occur in bile duct reconstruction. In an attempt to avoid bilioenteric anastomosis, which bypasses the biliary sphincter mechanism, various biologic and artificial materials have been employed clinically and experimentally to replace the damaged bile duct. No satisfactory biliary replacement material has yet been found. In the experimental model of bile duct stricture that has been presented, human amnion bile duct injuries mimicking those seen in clinical practice were repaired using human amnion as a free graft. Noncircumferential duct loss appeared to be satisfactorily repaired using amnion, and the amnion repair was found to be as good as or superior to plastic repair; however, circumferential duct loss was not adequately repaired with the amnion graft.
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Extrapancreatic fluid collections are a well-known complication of pancreatitis and may occur in unusual locations. Involvement of the left perirenal space is uncommon and has not yet been documented by computed tomography. One surgically proven case is described and pertinent radiologic findings are described.
A retrospective review of 106 cases of ruptured abdominal aortic aneurysm was undertaken to determine whether analysis of preoperative variables might be predictive of death in this condition. Thirty variables were analyzed by univariate and multivariate methods. Statistically significant differences between survivors and nonsurvivors were noted for 12 of 30 factors when analyzed with univariate tests. Multivariate analysis with stepwise logistic regression demonstrated that elevation of the unmeasured anion gap, a history of congestive heart failure, and the patient's level of consciousness before operation were significantly and independently associated with death. Coefficients generated from this model allowed stratification of patients into four risk groups with respective mortality rates of 100%, 75%, 28%, and 12%. We conclude that it is possible to assign a mortality risk score to individual cases of ruptured abdominal aortic aneurysm on the basis of readily available clinical and laboratory parameters. A prospective study to address this question seems justified.
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Myocardial ATP levels remain depressed following significant periods of ischemia (Isc) despite reperfusion (Rpf). Neither the rate of in vivo ATP return following global Isc nor the factors which influence recovery have been defined. In order to determine the time course to complete the return of ATP levels and evaluate methods of enhancing recovery of ATP levels, we have devised a chronic canine model of global Isc. In this model serial ventricular biopsies can be taken in the awake animal over several days without reoperation which allows an investigation of the recovery of the myocardium following a uniform global insult to be performed. Recovery of ATP levels has been shown to depend, at least in part, on the availability of precursors and the activity of the ATP regenerating enzymes. Because complete recovery of ATP levels takes days, short term (hours) models have limitations. Previous attempts at enhancing ATP recovery following Isc have been only partially successful because either the degree of depression was not great or the period of observation was short, resulting in incomplete return. To identify the best precursor choice, we previously measured the activity of the AMP regenerating enzymes, adenosine kinase (AdK) (adenosine----AMP) and adenine phosphoribosyl transferase (APRT) (adenine----AMP). Because APRT activity was 20 fold higher than AdK with similar Km values for substrates, it appeared that adenine (A) is preferred to adenosine for AMP regeneration in the dog's myocardium. The formation of 5-phosphoribosyl 1-pyrophosphate (PRPP) may also be rate limiting and, therefore, the effect of ribose (R) on ATP recovery was also evaluated. Recovery of ATP levels was assessed in three groups: (1) normal saline (NS), (2) A (20 mM) in normal saline (A/NS) or (3) A with R (80 mM) in normal saline (A/R) were infused (1.0 ml/min) into the right atrium of dogs for 48 hours following Isc. In all groups, ATP levels fell to between 46-60% of pre-Isc levels during Isc. In the NS dogs, ATP levels continued to fall slightly to 46% pre-Isc levels during the first four hours of Rpf after Isc. By 24 hours no appreciable recovery had occurred and the measured ATP was only 51% of the pre-Isc value. Even by seven days, ATP had not returned fully, and by extrapolation, complete recovery required 9.9 +/- 1.4 days. Treated dogs showed, however, that ATP recovery could be significantly enhanced.(ABSTRACT TRUNCATED AT 400 WORDS)
Two sisters with Coffin-Siris syndrome, born to healthy unrelated parents, are reported. The accurate X-ray evaluation of the two patients allows the identification of some new features and a better delineation of the radiological phenotype. Our two cases confirm the proposed autosomal recessive inheritance of the syndrome.
Cockayne syndrome is a well-known autosomal recessive form of dwarfism with senile-like appearance. Skeletal changes such as flattening of vertebral bodies, ivory epiphyses and thickening of cranial vault, have been observed in some patients with this condition. We describe here a 5.5-year-old girl with the typical clinical signs of Cockayne syndrome and a distinctive form of bone dysplasia with major involvement of the spine.
A congestive cardiomyopathy (CCM) model occurs in inbred broad-breasted turkeys and is manifested by reduced hatchability and a high mortality within a week of hatching. In the survivors, cardiac dilation begins by 3-4 weeks of age and further mortality occurs from chronic congestive heart failure. The mechanisms behind these changes is unknown, and, therefore, we investigated what role, if any, myocardial energy metabolism might play in these events. Ventricular myocardial samples were obtained for analysis of adenine nucleotides (ATP, ADP, AMP) and creatine phosphate (CP) in control and CCM turkeys, 1-31 days old. The adenine nucleotide energy charge (EC) was calculated using the formula EC = ATP + 1/2ADP/(ATP + ADP + AMP). We found the myocardial ATP levels and EC in CCM hearts at 1-2 days were reduced. In control turkeys, no significant age-related differences were found in myocardial high-energy phosphate compounds or in the EC. This depression in the energy metabolism of CCM turkeys may also be reflected in their poor hatchability. By 6-10 days, however, ATP levels had recovered and remained normal despite the onset of cardiac dilation and failure at 3-4 weeks of age in CCM turkeys. Because CP levels in control and CCM turkey hearts were similar in all age groups, significant ischemia did not appear to be present after hatching in CCM turkeys. Our results suggest, therefore, that an insult probably prior to hatching produced depressed myocardial energy levels in CCM turkeys and led to reduced hatchability. This early insult appears to be significant, in that late cardiac dysfunction resulted despite the recovery of myocardial ATP levels.
An infant boy with asymmetric crying facies, microcephaly, developmental retardation and failure to thrive is reported. His two siblings died in the newborn period because of complex congenital heart defects. The mother and the maternal grandmother have asymmetric crying facies, microcephaly and normal intelligence. A maternal aunt has severe physical and mental retardation, facial asymmetry, microcephaly, and cleft palate. This family allows an expansion of the spectrum of malformations associated with asymmetric crying facies and suggests autosomal dominant inheritance with variable expressivity.
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