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Biomedical subjects

J Hess

Publications and source records attributed to J Hess.

At least 199 records · Page 11Linked to original sources
PubMed1992

Effects of X-linked hemoglobin on in-vitro platelet function.

The in-vitro function of platelets in 1:1 mixtures of fresh whole blood and 10% DBBF alpha-alpha cross-linked hemoglobin in Ringer's acetate buffer was assessed by quantitative aggregation after challenge with common agonists and compared to the function of platelets in similar dilutions of whole blood in saline. Whole blood aggregometry was performed after addition of ADP, collagen, and ristocetin. Aggregation was quantified by measuring the change in impedance as drawn on the chart recording. No difference in mean impedance change was noted between the groups of blood samples which were incubated and tested in the hemoglobin solution and those incubated and tested in saline. In addition, incubation and stirring of the above mixtures over a period of six minutes without the addition of agonists did not result in spontaneous platelet aggregation. We conclude that alpha-alpha cross-linked hemoglobin, in the concentration studied, does not affect in-vitro platelet function, as measured by whole blood aggregometry.

Aspirin↗
PubMed1992

A modification of staged septation for univentricular atrioventricular connection.

A case is reported in which is described a modification of staged septation for univentricular atrioventricular connection with double-inlet left ventricle and left-sided rudimentary outlet chamber beneath the aorta. This modification diminishes the risk of atrioventricular conduction disturbances by gluing the perforated septation patch on the myocardium in the area overlying the central conduction system. Fixation of the patch was facilitated by exact fitting of the patch in this area, by ample contact of the patch and the myocardium in this area, and by immobilization of the patch because of equal pressures on both sides because of the perforation of the patch. In addition, this modification facilitates evenly drawing in of the ventricular free wall because already, in the first stage, the complete circumference of the patch is fixed, defining the maximal contribution of prosthetic material to the newly created septum.

Double Outlet Right Ventricle↗
PubMed1991

Transesophageal echocardiographic monitoring of interventional cardiac catheterization in children.

Transesophageal echocardiography was used prospectively in 22 children scheduled for interventional cardiac catheterization (9 with pulmonary valvuloplasty, 5 with aortic valvuloplasty, 1 with pulmonary angioplasty, 2 with aortic angioplasty, 2 with patent ductus arteriosus occlusion and 3 with Mustard baffle dilation) to determine its potential value as a monitoring technique. The patients ranged in age from 0.9 to 14.6 years (mean 5.4) and in weight from 9.5 to 49.2 kg (mean 21.1). Studies were completed in all patients without complications. Preintervention studies provided important new information in two patients, leading to cancellation of the planned procedure. Major contributions of transesophageal monitoring included 1) a real time assessment of catheter placement across either atrioventricular valve and the aortic valve during balloon valvuloplasty; 2) immediate assessment of aortic valve and aortic wall morphology during balloon dilation; and 3) detailed morphologic and hemodynamic information together with enhanced catheter guidance during Mustard baffle dilation. After pulmonary valvuloplasty, partial chordal rupture of the tricuspid valve was documented in one patient. In two patients, balloon catheter position was modified according to the transesophageal findings. The assessment of changes in pulmonary valve morphology and transcatheter occlusion of a patent ductus arteriosus was not enhanced by single-plane transesophageal monitoring. Pulsed wave Doppler studies contributed additional information in the assessment of immediate hemodynamic changes after interventional procedures. Transesophageal echocardiography is a new important guiding and monitoring technique during interventional cardiac catheterization procedures in children. It can provide additional real time imaging information, immediate identification of complications and assessment of hemodynamic changes.

Adolescent↗
PubMed1991

The vasopressin receptor of the blood-brain barrier in the rat hippocampus is linked to calcium signalling.

The signal transduction system of the vasopressin receptor in cerebral microvessels is not known but appears not to be adenylate cyclase/cyclic AMP. We determined the effect of arginine vasopressin (AVP) on the intracellular free calcium concentration [Ca2+]i in endothelial cells of isolated hippocampal microvessels of rats, using the fura-2 fluorescence technique. AVP administration caused a rapid and transient rise of cytosolic free calcium which was absent after extracellular calcium was removed, and could be blocked with the vasopressin V1 receptor antagonist, d(CH2)5 Tyr(Me)AVP. The vasopressin V2 receptor agonist, 1-deamino-8,D-AVP, on the contrary, failed to affect the intracellular free calcium level, and was unable to inhibit the AVP-induced rise of [Ca2+]i in the preparation. Our results, therefore, demonstrate the presence of a calcium-signalling, i.e. V1 vasopressin receptor at the blood-brain barrier in the hippocampus of the rat.

Animals↗
PubMed1991

Surgery for Ebstein's anomaly: the clinical and echocardiographic evaluation of a new technique.

Ten consecutive patients (age range 4 to 44 years, mean 22) underwent surgical repair of Ebstein's anomaly by vertical plication of the right ventricle and reimplantation of the tricuspid valve leaflets. No patient died during or after operation. Intraoperative postbypass echocardiography documented a good result in nine patients but severe tricuspid regurgitation in one patient, who then underwent prosthetic valve replacement during a second period of cardiopulmonary bypass. Two of four patients who had had right ventricular papillary muscle dysfunction in the early postoperative period showed improved papillary muscle function with concomitant reduction of tricuspid regurgitation 6 months later. All patients were evaluated clinically and by echocardiography 2 to 23 months later. All patients showed clinical improvement, seven by one functional class and three by two classes. All were in sinus rhythm. The mean cardiothoracic ratio decreased by 6% (p less than 0.05). On bicycle ergometry performed in six patients, peak oxygen consumption exceeded 20 ml/kg per min in five. Tricuspid regurgitation diminished in eight patients (by three grades in two patients, by two grades in five and by one grade in one patient); it remained unchanged in two. Comparison of preoperative and postoperative pulsed Doppler flow velocities across the pulmonary valve showed an increase in the peak velocity of flow across the valve (mean 83 +/- 14 versus 97 +/- 11 cm/s, p less than 0.005) and a decrease in the time to peak velocity (mean 130 +/- 16 versus 91 +/- 23 ms, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Aortic atresia with normal left ventricle: one-stage repair in early infancy.

Successful one-stage repair of aortic atresia with a left ventricle was performed in a 6-week-old infant using a new technique. After patch enhancement of the hypoplastic aortic arch, the transected proximal pulmonary artery was directly anastomosed to the aortic arch. An intraventricular baffle established continuity between the left ventricle and neoaortic valve, and a homograft conduit was inserted between the right ventricle and pulmonary artery bifurcation.

Anastomosis, Surgical↗
PubMed1991

Transesophageal echocardiography in evaluation and management after a Fontan procedure.

Transesophageal echocardiography was used in 18 patients (aged 1.6 to 34 years, mean age 12.6) to assess the immediate (5 patients) or intermediate (13 patients) results after a Fontan-type procedure. The findings were correlated with precordial echocardiographic (all patients) and cardiac catheterization (11 patients) data. Atrial shunting was documented by transesophageal studies in three patients (precordial in one patient). In two patients it was confirmed by cardiac catheterization; the third underwent reoperation based on the transesophageal study alone. Pulmonary artery obstruction was documented in three patients (precordial in one patient) and was confirmed by subsequent cardiac catheterization in all. Evaluation of anterior Fontan connections was successful in 5 of 8 patients (precordial in 6 of 8), and posterior connections in 10 of 10 patients (precordial in 5 of 10). A Glenn shunt could be evaluated in eight of nine patients (precordial in three of nine). Thrombus formation was detected by transesophageal studies in three patients (precordial in one patient); repeat studies were used to evaluate thrombolytic therapy in two. Atrioventricular valvular regurgitation (11 of 18 patients) was better defined by transesophageal than by precordial studies (5 of 18). A coronary artery fistula was identified in two cases (precordial in none). Transesophageal pulsed Doppler interrogation of pulmonary artery and pulmonary vein flow patterns consistently allowed a detailed evaluation of the Fontan circulation. Transesophageal echocardiography is an important diagnostic and monitoring technique after the Fontan procedure. In this series, it was far superior to precordial ultrasound evaluation and of substantial additional value to cardiac catheterization.

Adolescent↗
PubMed1991

One stage repair of aortic arch anomalies and intracardiac defects.

Between August 1985 and May 1990, 27 neonates and infants underwent combined correction of intracardiac and aortic arch anomalies through a median sternotomy. Coarctation (CoA) was combined with VSD (6), AVSD (2), Taussig-Bing (TB) heart (5), transposition of the great arteries (TGA) (1), TGA + VSD (2), congenitally corrected TGA + VSD (1) and VSD + myxoid stenotic outlet valves (1). Interrupted aortic arch (IAA) was combined with VSD (10) and TB heart (1). Two patients had IAA type B as well as CoA. Age at operation varied from 2 to 243 days with a mean age of 51 days. Twenty patients (70%) were younger than 30 days. One TGA + VSD and all TB hearts had maligned outlet septum and right ventricular outflow tract obstruction (RVOTO). Posterior outlet septum deviation and left ventricular outflow tract obstruction (LVOTO) occurred in 8 patients with malalignment VSD and IAA (7) or CoA (1). Aortic arch reconstruction was performed using extended end-to-end anastomoses. In 3 patients, arch hypoplasia necessitated patch implantation. VSDs were closed through the right atrium unless the anatomy dictated otherwise. One TB heart was reconstructed with a Kawashima procedure. All other TB hearts and all TGAs were corrected with arterial switch operation. Obstructing outlet septum was resected whenever necessary. Follow-up was complete and included echo-Doppler control. Eleven patients had postoperative heart catheterisation. Early mortality was 18.5% (5 patients). Persisting LVOTO or RVOTO was responsible. There was no late mortality. Five patients were reoperated upon: 3 for stenotic anastomoses and 2 for a subaortic membranous stenosis. Successful balloon dilatation of recoarctation was performed four times.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1991

The role of transoesophageal echocardiography in adolescents and adults with congenital heart defects.

Between April 1985 and December 1989, outpatient transoesophageal echocardiography was performed in 133 adolescent and adult patients (14% of all outpatient transoesophageal studies) (age range 11-78 years; weight 30-95 kg) to determine the value of this technique both in establishing the primary diagnosis (62 patients) and in the post-surgical follow up (71 patients) of congenital heart disease. The results were correlated with the findings of precordial echocardiography, catheterization and surgical inspection. Clear advantages of transoesophageal imaging over precordial imaging include: (1) direct identification of atrial appendage morphology in all patients; (2) delineation of systemic and pulmonary venous connections; (3) atrial baffle function (eight patients); (4) better evaluation of the Fontan-type circulation (five patients); (5) improved morphologic assessment of the atrioventricular junction and valves (29 patients); (6) definition of subaortic obstruction (18 patients); and (7) definition of ascending aortic morphology in Marfan's syndrome and supravalvar aortic stenosis (13 patients). The problems encountered with transoesophageal imaging include: (1) limited imaging planes; (2) poor visualization of specific intracardiac regions (antero-apical trabecular septum, right ventricular outflow tract); (3) flow masking behind implanted intracardiac prosthetic material.

Adolescent↗
PubMed1991

Role of intraoperative ultrasound examination in patients undergoing a Fontan-type procedure.

To determine its potential impact on perioperative surgical management intraoperative ultrasound examination (cross sectional imaging, colour flow mapping, pulsed and continuous wave Doppler) was used in 16 consecutive patients undergoing a Fontan-type procedure. Epicardial cross sectional imaging before bypass defined the precise intracardiac morphology in 15 of 16 patients. The preoperative morphological diagnosis was refined in four patients (25%), and this influenced surgical management in two (12%). Epicardial studies after bypass identified seven residual haemodynamic lesions in five patients (three residual intercardiac shunts, one ventricular outflow obstruction, one pulmonary artery obstruction, two mitral valve regurgitation), and led to immediate revision during a second period of bypass in three (18%). In one patient who required early reoperation residual shunting was not detected after bypass by either colour flow mapping or a contrast study. Final intraoperative studies showed a good surgical result in 14 patients (87%). Flow characteristics and flow velocities within the Fontan circulation could be assessed immediately after the patient came off cardiopulmonary bypass by means of combined pulsed wave Doppler and colour flow mapping in 14 of the 16 patients. Cross sectional studies of the left heart after bypass showed no change in ventricular function and allowed monitoring of volume replacement and ventricular filling. Intraoperative ultrasound was a valuable monitoring technique in patients undergoing a Fontan-type procedure. It refined preoperative diagnosis, monitored ventricular function, and identified or excluded residual haemodynamic lesions in most patients.

Adult↗
PubMed1991

Assessment of anomalous systemic and pulmonary venous connections by transoesophageal echocardiography in infants and children.

OBJECTIVE: To assess the value of transoesophageal echocardiography in the preoperative definition of systemic and pulmonary venous connections. DESIGN: Transoesophageal echocardiographic studies were performed prospectively under general anaesthesia in 76 consecutive unoperated children. Results were compared with those obtained by earlier transthoracic ultrasound studies (n = 76), cardiac catheterisation (n = 62), and subsequent surgical inspection (n = 58). SETTING: Two tertiary referral centres. PATIENTS: 76 unoperated infants and children (age 0.2-14.8 years, mean age 4.1 years) with congenital heart disease. MAIN OUTCOME MEASURE: Identification of anomalous systemic and pulmonary venous connections. RESULTS: Transoesophageal studies showed anomalous venous connections in 14 patients. Two had both anomalous systemic and pulmonary venous connections. Transoesophageal studies showed 12 anomalous systemic venous connections in nine patients. In eight patients these were confirmed at operation or catheterisation: one patient is awaiting operation. Six anomalous systemic venous connections were missed during earlier transthoracic studies. Anomalous pulmonary venous connections (one mixed total, six partial) were shown in seven patients. These were confirmed at operation in six and by cardiac catheterisation in one. Four of these patients were missed during earlier transthoracic ultrasound studies. No patient defined as having normal venous connections by the transoesophageal study was subsequently shown to have anomalous venous connections at operation or angiography. CONCLUSIONS: Transoesophageal echocardiography is a highly sensitive tool for the preoperative definition of systemic and pulmonary venous connections. In this series it was better than transthoracic ultrasound and complemented cardiac catheterisation and angiocardiography.

Adolescent↗
PubMed1991

[Distal radio-ulnar arthrodesis and Kapandji ulna segment resection in treatment of limited forearm rotation].

Between 1986 and 1990 distal radioulnar arthrodesis with segment resection of the distal ulna (Sauvé-Kapandji Operation) was performed in 31 patients with posttraumatic changes of the distal radioulnar joint; 26 patients could be examined after 10 to 44 months. At the time of examination, all patients had bony fusion between distal radius and ulna; forearm rotation improved by 60.5%, 55% of the patients had significant pain relief. Grip strength also improved postoperatively, though never reaching values of the healthy hand. Two patients developed a bony regeneration, which was successfully reoperated upon in one case, 81% of the patients reported an improved wrist function.

Arthrodesis↗
PubMed1990

[Closure of the persistent ductus arteriosus (Botalli) using a catheter procedure; the initial 50 patients treated in The Netherlands].

Experience gained with non-surgical catheter occlusion of patent ductus arteriosus in 50 patients (1-65 years) is described. Embolisation of the Rashkind device into the right pulmonary artery occurred in 1 patient. In another patient the device was removed because the prongs of the proximal umbrella could not be visualized. In 4 patients a considerable residual shunt was successfully treated with implantation of a second device. In 1 of these 4 patients this resulted in disappearance of considerable haemolysis as well. Five patients, however, still have a--haemodynamically insignificant--residual shunt. In 43 patients catheter occlusion of the ductus arteriosus was 100% successful. The advantages and disadvantages of this method are briefly compared with those of surgical treatment.

Adolescent↗
PubMed1990

[Cardiac findings in alcoholic liver disease].

In a prospective study 53 patients with alcohol-induced liver disease (fatty liver in 27, cirrhosis in 26) were studied clinically and with non-invasive techniques (electrocardiogram, systolic time intervals, M-mode echocardiography, upright bicycle stress test) to detect a possible cardiac involvement. Mean daily alcohol consumption was comparable in both groups (136 g/day over 16 years vs 124 g/day over 14 years). 15 to 41% of patients (more patients with fatty liver) complaint of angina pectoris and dyspnea at exercise or had palpitations. Echocardiography and systolic time intervals demonstrated in both groups (in patients with cirrhosis despite of a more intensive therapy with digitalis and diuretics) a marked enlargement of left ventricular dimensions with a significant (p less than 0.05) degree of dysfunction (PEP/LVET). Electrocardiography showed abnormalities in 26 to 44% of patients: signs of right ventricular enlargement in 26% of patients with fatty liver, and a prolongation of myocardial repolarisation (QTc) in 44% of patients with cirrhosis. Patients with alcohol-induced liver disease deserve more attention of their cardiac complaints, clinical and functional findings.

Adult↗
PubMed1990

Balloon angioplasty for the treatment of native coarctation: results of Valvuloplasty and Angioplasty of Congenital Anomalies Registry.

Data on dilation of 141 native coarctation procedures in 140 patients between 3 days and 29 years of age were submitted to the Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry. Fifteen patients were less than 4 weeks old, 15 between 1 month and 12 months old and 110 patients over 1 year old. The immediate results confirmed that native coarctations could be effectively dilated in both infants and older children. The data do not support any conclusions concerning balloon size relative to results or complications. There were 24 complications (17%) reported with 1 death after 3 days and after intervening surgery in an infant with associated persistent ductus arteriosus. There were 2 early and 6 late "aneurysms" reported after the coarctation dilations with insufficient immediate and no long-term information about the significance of these. The VACA Registry data suggest that dilation of native coarctations can be performed effectively and relatively safely but do not answer whether this procedure should be performed.

Adult↗
PubMed1990

Analysis of the haemolysin secretion system by PhoA-HlyA fusion proteins.

We studied the efficiency of the pHly152-derived haemolysin transport system using PhoA-HlyA fusion proteins and different constructs which provide HlyB/HlyD in trans. The optimal C-terminal HlyA signal consists of the last 60 amino acids. Longer stretches of HlyA do not improve the transport efficiency of PhoA-HlyA fusion proteins. The introduction of deletions and/or replacements in the 60 amino acid HlyA signal domain revealed at least three functional regions with different degrees of specificity. Amino acids 1-21 (numbered from the N-terminal part of the 60 amino acid HlyA signal), termed region I, could be replaced by a Pro-containing peptide. The other two regions II and III (amino acids 22-40 and 41-60, respectively) seem to interact directly with the HlyB/HlyD translocator since a PhoA fusion protein which contains either of the two regions was still secreted in a HlyB/HlyD-dependent mode, albeit at low efficiency. An efficient trans-complementing HlyB/HlyD system was only obtained from the pHLy152-encoded hly determinant when the regulatory hlyR element was provided in cis. Secretion of the PhoA-HlyA fusion protein did not interfere with the secretion of HlyA even when the fusion protein was induced to a high level. This suggests that the capacity of the HlyB/HlyD translocation system is high and not normally saturated by its natural HlyA substrate.

Amino Acid Sequence↗