Biomedical subjects
Publications and source records attributed to T Schroeder.
We report a case of a vesicouterine fistula subsequent to delivery at cesarean section through the bladder. A first attempt to close the fistula failed but a second operation adhering to the general principles of fistula repair was successful.
The foetal Potter's syndrome represents a relatively frequent malformation syndrome, the incidence being 0.3% of all live births. The phenotypical changes seen in these newborn occur in complete bilateral renal agenesia = the original Potter's syndrome, but they are also found in various congenital cystic diseases of the kidneys and/or the other urinary organs. In additional to the original Potter's syndrome, a patho-anatomical classification of cystic deformations of the kidneys or of the efferent urinary organs was introduced by Osathanondh and Potter (1976) (Potter Type I-Type IV). These severe foetal malformations can be diagnosed at least in part via timely ultrasonic examination during the first half of the pregnancy period. In such cases, an oligoamnion or sometimes an anhydramnion is regularly observed as principal sign. This diagnosis is probably confirmed if the foetal urinary bladder is not demonstrable following application of furosemide (Campbell). Occasionally the cystic changes of the urinary organs can be proven direct by means of sonography. Ten examples of cases are described presenting the typical ultrasonographic findings in the so-called extended "Potter's syndrome" (oligoamnion or anhydramnion, malformations of the kidneys and/or the efferent urinary organs and phenotypical changes). Due to their infaust prognosis these foetal diseases result in the indication for termination of pregnancy.
The article reports on the ultrasonographic diagnosis of a Meckel-Gruber's syndrome in the 17th week of pregnancy. This malformation syndrome is characterized by the triad: encephalocele, polycystic kidneys, and polydactyly. This congenital disease is compared with malformation syndromes which are distinguishable by differential diagnosis, such as Potter's renofacial syndrome. Thorough ultrasonic examination will be able to detect the severe renal changes as well as the neural tube defects associated with Meckel-Gruber's syndrome. Further diagnostic aids for detecting neural tube defects are, in the first place, the alpha-fetoprotein values obtained from the serum of the mother and/or the amniotic fluid, as well as the determination of acetyl cholinesterase.
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During a 10-year period, 60 patients were operated on for occlusive lesions in the brachiocephalic trunk and/or the subclavian arteries proximal to the vertebral artery. Angiography showed 68 occlusive lesions, of which 64 were treated surgically. Of these, 47 exhibited subclavian steal. Sixty-three reconstructive procedures were performed together with two arterial ligations (four patients were operated on bilaterally and one patient was operated on twice on the same side). There were 30 transthoracic procedures, essentially endarterectomies, and 35 supraclavicular procedures, mostly carotid-subclavian bypasses and transpositions of the subclavian artery to the common carotid artery. One patient died (1.5 per cent). Serious complications occurred in additional four cases. In the follow-up study data on all the patients were available. During the follow-up period, ranging from four to 124 months (mean 43 months) seven patients died - none of cerebral ischemia. Based on blood pressure recordings and in doubtful cases, angiography, we found a cumulated five-year patency rate of 76 per cent. Seventy per cent of the patients considered their condition after operation to be improved, 26 per cent unchanged and three per cent worsened. Twice as many patients could work after the operation as before. The cumulative survival rate was found to be somewhat lower than that of a normal population.
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Three homogeneous glycoproteins were isolated from reduced and S-carboxy-methylated canine tracheal pouch mucus by gel filtration and ion-exchange chromatography. Initial fractionation was carried out on Sephadex G-200; chromatography of the excluded Sephadex G-200 fraction on Bio-Gel A-15 m yielded two high molecular weight glycoprotein fractions. Following rechromatography on the same column, the main fraction behaved as an electrophoretically homogeneous high molecular weight (581 600) glycoprotein, with a high carbohydrate content (80%) and a single amino-terminal amino acid (arginine). Ion-exchange chromatography (DEAE-cellulose) of the included Sephadex G-200 fraction yielded two electrophoretically homogeneous glycoproteins of lower molecular weight (20 800 and 24 600, respectively). A single amino-terminal amino acid, glycine and alanine, respectively, was detected for each glycoprotein. Chemical analysis of these three glycoproteins revealed the presence of fucose, galactose, N-acetylgalactosamine, N-acetylglucosamine, N-acetylneuraminic acid and sulfate monoester. The high molecular weight glycoprotein had a higher hexose, sialic acid and sulfate content, per mg of protein, than the low molecular weight glycoproteins. The results of the alkaline borohydride treatment indicated that the majority of the carbohydrate chains of these glycoproteins are linked to the protein core through O-glycosidic bonds involving N-acetylgalactosamine and serine or threonine.
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Due to their selectivity towards voltage-sensitive calcium channels (VSCCs) omega-conotoxins are being exploited as a new class of therapeutics in pain management and may also have potential application in ischaemic brain injury. Here, the structure-activity relationships (SARs) of several omega-conotoxins including GVIA, MVIIA, CVID and MVIIC are explored. In addition, the three-dimensional structures of these omega-conotoxins and some structurally related peptides that form the cysteine knot are compared, and the effects of the solution environment on structure discussed. The diversity of binding and functional assays used to measure omega-conotoxin potencies at the N-type VSCC warranted a re-evaluation of the relationship between these assays. With one exception, [A22]-GVIA, this analysis revealed a linear correlation between functional (peripheral N-type VSCCs) and radioligand binding assays (central N-type VSCCs) for the omega-conotoxins and analogues that were tested over three studies. The binding and functional results of several studies are compared in an attempt to identify and distinguish those residues that are important in omega-conotoxin function as opposed to those that form part of the structural scaffold. Further to determining what omega-conotoxin residues are important for VSCC binding, the range of possible interactions between the ligand and channel are considered and the factors that influence the selectivity of MVIIA, GVIA and CVID towards N-type VSCCs examined.
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The intravascular oxygenator and carbon dioxide removal device (IVOX; CardioPulmonics, Salt Lake City, UT) has been shown to perform 30% of the gas exchange in animals and patients with acute respiratory failure. Among the factors that limit gas exchange is the mass transfer resistance in the blood phase. To determine if a reduction in mass transfer resistance by mixing venous blood can enhance the O2 transfer and CO2 removal by IVOX, a right atrium-pulmonary artery venovenous bypass circuit was used in sheep to model the adult vena cava. A size 9 IVOX (894 fibers with 0.41 m2 surface area, n = 5) was incorporated in the bypass circuit and the blood flow controlled by a roller pump ranging from 1 to 4 l/min. An intra-aortic balloon was placed near the shaft of the IVOX and pulsated at the rate adjusted to best improve CO2 removal (100-120 bpm). O2 transfer and CO2 removal were measured with balloon pulsation on and off at different flow rates. Results showed that blood mixing by pulsation of the balloon caused a 25-49% increase in O2 transfer by IVOX, and this increase remained relatively constant throughout the full flow range. CO2 removal was also increased by up to 35%, but at flows between 3.5 and 4 l/min, the effect of mixing was diminished. It is concluded that reduction in the mass transfer resistance by blood mixing improves gas exchange. Because O2 is more diffusion limited, it is more dependent upon mixing of blood for gas exchange than CO2. More design improvements to incorporate active mixing may further enhance the gas exchange performance of IVOX.
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Cerebral blood flow was measured by the intravenous xenon-133 technique at rest and during cerebral vasodilation with acetazolamide in 32 patients before and after uncomplicated carotid endarterectomy. The results were compared with the internal carotid artery perfusion pressure measured during surgery. A significant improvement in side-to-side cerebral blood flow asymmetry occurred in 6 patients studied at baseline and in 11 patients during provoked cerebral vasodilation. These patients all belonged to a group of 14 patients who, in addition to a severe stenosis of the internal carotid artery, presented a reduction in cerebral perfusion pressure of at least 20%. No improvements occurred in 18 patients with no or only minor reduction in perfusion pressure, irrespective of the degree of stenosis. These findings indicate an improved perfusion reserve following carotid endarterectomy in most patients with marked reduction in perfusion pressure, whereas only some of these patients will experience an improvement in baseline cerebral blood flow.
Between 1979 and 1988, 656 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed in 287 patients (44%) and acute operation in 369 patients. A ruptured aneurysm was found in 218 patients (33%). Patients with arteriosclerotic heart disease, hypertension, impaired renal function or chronic pulmonary disease showed an increased perioperative mortality. Development of postoperative cardiac and renal complications could not be related to previous cardiac or renal diseases. The major postoperative complications were renal failure in 81 patients (12%), pulmonary insufficiency in 77 patients (11%) and cardiac complications in 96 patients (13%). Failure of one or more organs occurred in 153 patients (23%) and the mortality rate for patients with multiorgan failure was 68%. Complications leading to reoperation occurred in 93 patients (14%). The perioperative mortality was 18.8%. The mortality for elective cases was 4.8%, for symptomatic cases 17.2% and 37% for ruptured aneurysms. The five-year survival rate was 48% for ruptured aneurysms, 70% for symptomatic cases and 75% for elective cases. After six months the life expectancy in these three groups of patients were identical and comparable to the expected survival for a sex and age matched control population.