Failure factors in multi-institutional systems formation.
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Biomedical subjects
Publications and source records attributed to S Hunter.
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Rabbit antisera have been produced to an acute myelomonocytic leukaemia (AMML)-derived cell line (RC2a) and a histiocytic lymphoma derived cell line (U937) having macrophage characteristics. The antisera were screened by complement-mediated cytotoxicity and immunofluorescence (cytofluorograph analysis) against separated leukaemic (122 patients plus 13 cell lines) and normal haematologic cell populations (60 preparations from 20 donors plus 10 B-lymphoblastoid cell lines). The sera were absorbed with pooled B-lymphoblastoid cell lines including the autologous B-lymphoblastoid cell line to RC2a (CESS-B) or alternatively with B-CLL and T-CLL cells. All leukaemic cell populations were confirmed using the markers SIg, E-rosette receptor, cALL antigen, alpha-naphthyl butyrate esterase and myeloperoxidase. Rabbit anti-RC2a (Adherent cells) (RARC2a(Ad) ) and rabbit anti-U937 (RAU937) recognised antigens common to immature myeloid monocyte and T-lymphocyte lineage but did not react by cytotoxicity, absorption or cytofluorographic analysis with cells of B-lymphocyte lineage (B-lymphoblastoid or B-CLL) and reacted only occasionally with cALL patients' cells (includes pre B phenotype). These sera reacted with peripheral blood monocytes but not with other mature blood leucocytes. RAU937 reacted with a major mononuclear population from normal marrow and with more differentiated myeloid leukaemia cells. RARC2a(Ad) and RAU937 detected overlapping subgroups of myeloid leukaemia (AMoL, AMML, AML and CML) patients and Null-ALL and T-ALL patients. These subgroups are now being examined for prognostic significance.
An analysis system has been developed to aid the quantitative interpretation of echocardiograms. A small and relatively inexpensive desk-top computer, which requires no modification is used. The analysis system enables a variety of complex continuous measurements to be made. The include left ventricular dimension changes, velocities and "work" diagrams. Using the digitiser in the system, a series of options in the operating program allow the analysis steps to be tailored to specific clinical or research requirements. Analysed waveforms can be output singly or superimposed to allow physiological and measurement variabilities to be studied. The system is now being used in several hospitals, and all report favourably on its flexibility and ease of use.
To evaluate the ability of two dimensional echocardiography to identify and classify ventricular septal defects, 280 infants and children with clinically significant ventricular septal defects were studied. Multiple precordial and subcostal echocardiographic planes were scanned in each patient in an attempt to identify the defects. Defects visualised were classified on the basis of the structures which formed their margins. Subsequent correlation of this information with angiographic (280 patients), surgical (130 patients), and pathological (31 patients) data confirmed that defects in the following sites produced a specific two dimensional echocardiographic pattern. (a) Perimembranous inlet, (b) perimembranous outlet, (c) muscular inlet, (d) single trabecular, (e) muscular outlet, and (f) doubly committed subarterial. A defect was identified and correctly classified in 252 patients. Individual defects were identified with varying degrees of accuracy. All subarterial (24 patients) defects were correctly identified and classified, as were muscular defects of the inlet (18 patients) and outlet (six patients) septa. Of the 185 perimembranous defects, 182 were identified. Only 23 of the 43 single trabecular defects were identified. Small multiple ("Swiss cheese") defects (four patients) were not identified. We conclude that two dimensional echocardiography provides a reliable non-invasive method of identifying and classifying the following ventricular septal defects: (a) perimembranous defects, (b) doubly committed subarterial defects, and (c) muscular defects of the inlet and outlet septa. In our experience it fails consistently to visualise defects in the trabecular septum.
Fifty-two patients with pure mitral stenosis (27 with severe stenosis and 25 with mild stenosis) were studied to assess the ability of different M-mode echocardiographic measurements to separate mild and severe disease. Variables related to valve motion, for example diastolic closure rate, the mitral valve closure index, and the amplitude of valve motion, accurately divided patients with mitral stenosis from normal subjects but did not distinguish usefully between mild and severe disease. In contrast, variables dependent on left ventricular dimension change in diastole, for example the rapid filling period and the peak rate of left ventricular diastolic dimension change, accurately separated mild and severe disease. No patient with severe mitral stenosis had a rapid filling period, whereas 21 of the 25 patients with mild disease did have one. The peak rate of left ventricular diastolic dimension change was less than 10 cm/s or less than 2.4 cm/s per cm when normalised for left ventricular dimension in all patients with severe disease and in only six of the 25 patients with mild disease.
Twenty-three patients with total anomalous pulmonary venous connection were studied by two-dimensional echocardiography. In all cases the diagnosis was made before invasive procedures, with surgical or angiocardiographic confirmation. Eleven patients had supracardiac drainage (three to the coronary sinus, two to the right atrium,) and seven had infracardiac drainage. In the majority of cases the precise pattern of drainage could be identified by combining suprasternal, praecordial, and subcostal views. In 12 cases where the suprasternal cut was used a pulmonary venous confluence could be identified, having a cross-like structure in nine, with three others appearing as a dilated channel behind and separate from the left atrium. Thus, two-dimensional echocardiography reliably makes the diagnosis of total anomalous pulmonary venous connection and in the majority the precise pattern of drainage can be determined.
A case is described of congenitally corrected transposition of the great arteries (atrioventricular discordance, ventriculoarterial discordance) with interrupted aortic arch, a previously unreported association. Aortic continuity was achieved by direct surgical anastomosis. Pulmonary artery banding was subsequently necessary, because of heart failure associated with a large ventricular septal defect. A possible pathogenetic mechanism is suggested.
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Inasmuch as this special issue of the knee is dedicated to the clinician, the clinical approach to biomechanical analysis has been presented. Through the use of biomechanical analysis, the clinician can select positions of exercise that stress certain structures while minimizing stress to other structures.
The conduction tissue in a univentricular heart of the right ventricular type with a right-sided rudimentary chamber was studied. Both an anterior and conventional node were found, the anterior node being positioned in the atrial septum very close to the conventional node. Between the two nodes, a sling of conduction tissue passed through the annulus fibrosus but was not related to the trabecular septum. A non-branching bundle descended on to a free-running trabecula in the main ventricular chamber, the trabecular septum itself being devoid of conduction tissue. We believe it is likely that this trabecula represents the trabecula septomarginalis of the normal right ventricle. It has recently been suggested that during development the primordium of the trabecula septomarginalis is the structure which carries the conduction tissue from the atrioventricular node (whatever its position) to the trabecular septum. The present findings seem to support this.
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Seventeen cases are described in which both atria connect directly to a chamber with right ventricular characteristics. The atria connected through separate atrioventricular valves in six hearts and a common valve in 11. All hearts had a posterior rudimentary chamber. The septum which separated it from the main chamber was directed to the crux of the heart. Ten hearts were from patients with atrial situs solitus and seven from patients with atrial situs ambigous. Arterial connections were concordant in three cases, had a double outlet from the main ventricular chamber in nine and single outlet of the heart in five. The patent artery always arose from the main chamber, with pulmonary atresia in three and aortic atresia in two. This and other studies indicate that double inlet atrioventricular connection does not predict the morphology of the main chamber. Although usually associated with a main chamber of left ventricular type, it may also be associated with a main chamber having right ventricular characteristics. Both types should be considered as univentricular hearts; the posterior chamber in hearts of right ventricular type are analogous to the anterior chamber in univentricular hearts of left ventricular type and are a rudimentary chamber rather than a hypoplastic ventricle. In the right ventricular form of univentricular heart, the trabecular zone of the rudimentary chamber is of left ventricular type.
The study included 916 schistosomal patients and 97 controls. The prevalence of HBs-Ag and anti-HBs was significantly higher in the bilharzial patients compared to controls. Their frequency was higher in the ascitic than the hepatosplenic group, and the difference between each and the simple group was highly significant. Cases with current jaundice showed highly significant frequency of both HBs-Ag and anti-HBs compared to those with no history or manifest jaundice at the time of study. In addition, cases with raised bilirubin, SGPT and SGOT showed significantly higher frequency of HBs-Ag and anti-HBs compared to cases having normal levels. On the other hand, the frequency was not affected by the level of serum alkaline phosphatases. As regards liver pathology, cases with mixed pathologic picture showed significantly higher frequency of both HBs-Ag an anti-HBs compared with those having pure schistosomal lesions.