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Biomedical subjects

G Ziemer

Publications and source records attributed to G Ziemer.

At least 109 records · Page 6Linked to original sources
PubMed1987

Truncus arteriosus type A3: complex repair with cryopreserved pulmonary homograft.

A 6-year-old girl with truncus arteriosus type A3, one of the rarest anatomic types, underwent corrective surgery using a cryopreserved valved pulmonary homograft. The special anatomic features in this case were individual origin of the pulmonary arteries. The right pulmonary artery came directly off the truncal vessel, whereas the left pulmonary artery was connected to the aortic arch via a stenotic ductus or ductus-like vessel. The preoperative pulmonary blood flow distribution was 94% on the right versus 6% on the left side. The underperfusion of the left lung may have been related to pulmonary hypoplasia due to long lasting stenosis at the left pulmonary artery take off. The postoperative pulmonary blood flow distribution was 67% on the right versus 33% on the left side. The operative and postoperative course has been uneventful; presently, 6 months after the operation, the patient is in improved clinical condition.

Angiocardiography↗
PubMed1987

Biological sealants and knitted Dacron conduits: comparison of collagen and fibrin glue pretreatments in circulatory models.

To assess the healing characteristics of knitted Dacron conduits sealed with fibrin glue, collagen cross-linked with glutaraldehyde, and collagen cross-linked with formaldehyde, composite conduits, each constructed from two of the three test materials, were implanted in the pulmonary and systemic circulations of sheep and dogs for 3 and 6 months. Relative rates and morphologies of sealant resorption and other histological findings were predicted by a previous study involving subcutaneous implantation of the same graft materials in the rat. In particular, both studies revealed that delayed resorption of collagen cross-linked with glutaraldehyde and collagen cross-linked with formaldehyde resulted in lack of adhesion between inner capsule and conduit, thereby causing focal hemorrhagic dissection in the circulatory implants. There were no important qualitative or quantitative differences in healing between sheep and dogs or in pulmonary versus systemic location of the conduit. Rendering an animal cyanotic by placing a pulmonary arterial-left atrial shunt or by increasing or decreasing the intraconduit systolic pressure did not obviously affect healing. The results emphasize that the biological consequences of sealed grafts are strongly dependent on the sealant material. Porosity control of knitted Dacron with biological sealants that undergo minimal or delayed resorption may lead to poor tissue adhesion and resultant complications.

Animals↗
PubMed1987

The influence of a right-to-left cardiac shunt on lidocaine pharmacokinetics.

The pharmacokinetics of lidocaine were studied in 1-2-month-old lambs with surgically created, intracardiac right-to-left shunts (RLS) and in age-matched control lambs. Shunts were prepared by anastomosing the pulmonary artery to the left atrial appendage to achieve arterial oxygen saturation of 65-75%. Catheters were implanted both in the right atrium for drug infusion and in the ascending aorta for blood sampling. Lidocaine, 1 mg/kg, injected as a rapid bolus, or 12 mg/kg, injected as a continuous infusion over 15 min, was delivered into the right atrium. Serial samples of arterial blood were obtained every 2.5 s for 1 min following the bolus injection and up to 4 h following the continuous infusion. Samples were analyzed for lidocaine by gas chromatography. Peak arterial whole blood concentration of lidocaine in the shunted animals was 37.0 +/- 2.1 micrograms/ml compared to 21.1 +/- 0.1 microgram/ml in the control animals; P less than .01. The peak arterial concentrations during the lidocaine infusion were 12.6 +/- 3.5 micrograms/ml in the RLS and 5.8 +/- 1.5 micrograms/ml in the controls. Total body clearance of lidocaine was decreased in the shunted animals to 30.7 +/- 13.2 ml.kg-1.min-1 from 68.1 +/- 12.1 ml.kg-1.min-1 in the control animals; P less than .001. The steady-state volume of distribution was also decreased in the shunted animals, 1.0 +/- 0.2 l/kg versus 2.0 +/- 0.7 l/kg in the controls; P less than .02. To induce convulsions 4.75 +/- 0.46 mg/kg of lidocaine was required in the shunted animals and 7.37 +/- 0.44 mg/kg in the control animals (P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Surgery for coarctation of the aorta in the neonate.

Between 1972 and 1984, 100 consecutive neonates (less than or equal to 30 days old) underwent repair of coarctation of the aorta. Mean (+/- SD) age at operation was 12.0 +/- 8.0 days; mean weight was 3.1 +/- 0.5 kg. Simple coarctation was present in 29 patients (group I), 32 patients had additional ventricular septal defects (group II) and 39 patients had additional complex heart disease (group III). An associated patent ductus arteriosus was present in a total of 81 patients. Subclavian flap angioplasty (SFA) was performed in 70 patients, resection and end-to-end anastomosis (E-E) in 24 patients, and miscellaneous procedures in six patients. All SFA procedures were performed after 1977, and 87.5% of E-Es were done before 1977. The early mortality was 33.3% for patients undergoing E-E and 11.4% for those undergoing SFA. Freedom from reintervention for recoarctation after 5 years was 92.9% for patients who underwent E-E and 75.2% for those who underwent SFA. Actuarial survival at 4 years was 85.5% for group I, 79.9% for group II, and 42.9% for group III. Follow-up was 97.7% for a mean (+/- SD) of 41.9 +/- 37.1 months. It is likely that some of the differences between patients undergoing SFA and E-E with respect to early mortality and freedom from reintervention are due to the different time frames during which the procedures were done. However, neonatal ductal tissue after SFA may contract and fibrose causing recoarctation, while disadvantages related to the circumferential suture line after E-E may have been overemphasized in the past. A prospective randomized trial of these two techniques is warranted.

Aortic Coarctation↗
PubMed1985

[Massive hemorrhage following multiple epidural punctures as a late complication in thrombocythemia].

We present a female patient in whom numerous lumbar punctures for epidural anaesthesia were followed by a delayed development of a large subcutaneous haematoma in the lumbar region. The outcome was fatal. The patient's basic disease was found to be chronic myeloic leukaemia that had caused an excessive elevation of platelet count. We, therefore, suggest that lumbar punctures for epidural anaesthesia should be approached with extreme care in cases of thrombocytaemia. If possible, repeated punctures for the placement of epidural catheters should be avoided.

Aged↗
PubMed1984

[Treatment of acromioclavicular dislocations with the Balser hook plate and ligament suture].

The method of operation is described, making the ligament suture safe with the hook-plate. A postoperative immobilisation is renounced by this supplying. The results of the follow-up examinations (n = 20) show no disadvantage to other operative methods. As the subjective complaints and the rate of arthrosis appear to be lower than with usual procedures of stabilisation, the supplying with the hook-plate according to Balser (additional to the ligament suture) seems to guarantee a particularly safe retention under biomechanical favourable conditions.

Acromioclavicular Joint↗
PubMed1983

[A rare form of vascular ring in association with transposition of the great arteries: left-sided course of the aortic arch with arteria lusoria and a right-sided persistent Botalli's duct].

This report describes the successful resection of an asymptomatic vascular ring in a one year-old girl performed at the time of an atrial-switch operation for transposition of the great arteries (d-TGA). This particular form of vascular ring, left-sided aortic arch, left descending aorta with retroesophageal segment and right-sided ductus arteriosus with its origin from a right-sided Kommerell's diverticulum, is extremely rare and, apparently, an ipsilateral course of the aortic arch and descending aorta has not been previously described in association with this vascular ring. The peculiarities in this case cannot be explained on the basis of the majority of known literature on classification of vascular rings. Only those classifications describing the retroesophageal segment of the ring and documenting the lateral localization of the descending aorta as an inclusion criterion are capable of accommodating this case. Based on this criterion, similar presentations may also be delineated. An autopsy report of Rheder et al. appears similar to the case at hand but the description did not include the localization of the descending aorta.

Cardiac Catheterization↗
PubMed1982

Malfunction of a St. Jude medical heart valve in mitral position.

Early postoperative intermittent malfunction in a St. Jude mitral valve prosthesis is described. The patient underwent reoperation and had an uneventful recovery. After explantation, the prosthesis underwent laboratory examination. The findings included a minimal disproportion between leaflets and valve ring causing intermittent inhibition of leaflet motion. The unpredictable irregularity of the malfunction phenomenon in vivo, confirmed by laboratory investigations, is explained as a result of a changing myocardial tension status sufficient to alter the ring to leaflet proportion of the valve in either direction.

Adolescent↗
PubMed1982

[Excretion of methylated nucleosides in the initial therapy phase in a case of anorexia nervosa].

The urinary excretion of six methylated ribonucleosides was measured in a case of anorexia nervosa during the first eight weeks of therapy. Four phases can be distinguished. Highly elevated values are found in a clearly catabolic situation. Immediately after onset of therapy when catabolism is stopped but nutrition still inadequate the excretion of RNA-catabolites is lowered markedly. As soon as normocaloric nutrition is reached after two weeks, a short but clearcut peak-excretion can be observed. Finally, the excretion of methylated RNA-catabolites is stabilized on an intermediate level after three to six weeks, when nutrition is constantly normocaloric and weight continues to increase linearly.

Adenosine↗
PubMedDate not supplied

Cerebral ultrasonography before and after cardiac surgery in infants.

Cerebral ultrasonography was performed in 66 infants before and after open heart surgery in order to study the incidence of cerebral complications. The underlying cardiac malformations were ventricular septal defect (n = 28), transposition of the great arteries (n = 11), tetralogy of Fallot (n = 8), complete atrioventricular septal defect (n = 5), total anomalous pulmonary venous drainage (n = 3), truncus arteriosus communis (n = 2), and complex cardiac malformations (n = 9). In 60 of the 66 infants ultrasonography of the brain preoperatively was normal, 3 had minor structural abnormalities, and 3 had ventriculomegaly of various degrees. Postoperatively, 46 infants had a normal brain ultrasound scan; 6 had slight structural abnormalities; and 5 had slight symmetric or asymmetric widening of the ventricles. Five infants showed severe ventriculomegaly with cerebral atrophy, and in 4 patients there was intracerebral hemorrhage, associated in 2 cases with severe ventriculomegaly. On repeat examinations it was found that up to 4 weeks after the operation an initially normal cerebral ultrasound scan could convert to a pathologic one. Most of those children who showed significant deterioration on the cerebral ultrasound scan suffered from complex cardiac malformations or had severe problems during the postoperative period.

Brain Damage, Chronic↗
PubMedDate not supplied

Value of transesophageal color Doppler echocardiography for detection of different types of atrial septal defect in adults.

In 121 adults, the value of transthoracic and transesophageal color Doppler echocardiography for detection of different types of atrial septal defect (ASD) or of partial anomalous pulmonary venous return was analyzed. The 121 patients had a total of 129 defects with left-to-right atrial shunting (including eight patients with two types of defects). All of six cases with primum-type ASD were diagnosed correctly by both echocardiographic methods. Ninety-seven patients showed a secundum-type ASD during transesophageal echocardiography: by transthoracic echocardiography, only eight (20%) of the 40 small defects (diameter < 5 mm) were detected as compared with 15 (83%) of the 18 defects with a diameter of 5 to 10 mm and all 39 defects with a diameter > 10 mm. A sinus venosus--type ASD was evident by transesophageal echocardiography in 11 patients, of which only one (9%) was demonstrated by the transthoracic approach. Partial anomalous pulmonary venous return was seen by transesophageal echocardiography in 13 patients but missed in two other patients in whom anomalous pulmonary venous return was subsequently identified by surgery (both with anomalous return of the upper right pulmonary vein into the superior vena cava). By use of the transthoracic technique, partial anomalous venous return was detected in only two cases, both of which had "scimitar syndrome." Compared with transthoracic echocardiography, the transesophageal approach is clearly superior in the detection of small secundum-type ASD, sinus venosus--type ASD, and partial anomalous pulmonary venous return.

Adolescent↗
PubMedDate not supplied

Cytokine gene expression in monocytes of patients undergoing cardiopulmonary bypass surgery evaluated by real-time PCR.

Cardiopulmonary bypass (CPB) surgery induces systemic release of proinflammatory cytokines causing unspecific inflammatory reactions. This study deals with the development of a sensitive technique for detecting changes at the mRNA level in monocytes of patients undergoing CPB surgery, by using real-time PCR. Blood samples from patients undergoing elective coronary artery bypass grafting were obtained at six different time points. RNA was extracted from isolated monocytes and cDNA was synthesized by reverse transcriptase. CPB surgery induced gene expression of IL-1beta, IL-6, IL-8, and TNF-alpha, followed by a decrease below the preoperative expression values 6 h post CPB. High significant increases in gene expression for IL-8 at the end of surgery (p = 0.001) were detected. Real-time PCR is a powerful tool for getting simultaneously numerous sensitive, accurate, and reliable results from small amounts of biological material. This method avoids time-consuming and hazardous post-PCR manipulations and decreases the potential risk of PCR contamination.

Aged↗
PubMedDate not supplied

Comparison of pulsatile and nonpulsatile perfusion of the lung in an extracorporeal large animal model.

OBJECTIVE: Extracorporeal lung-perfusion models are widely used to evaluate pulmonary preservation techniques and reperfusion injury. However, these models mainly depend on nonpulsatile flow, which is not physiological and can subsequently lead to pulmonary edema. Observation in a standardized setting and reliability of functional and structural data assessment are therefore limited. To overcome these limitations we developed a new extracorporeal large animal lung perfusion model utilizing pulsatile flow to perfuse the pulmonary vasculature. METHODS: Lungs of juvenile domestic pigs were in situ preserved with 2 liters Perfadex and stored for 3 h at 10 degrees C. Thereafter, reperfusion of the lung was performed in an extracorporeal blood perfusion circuit employing either a modified roller pump with pulsatile module (300 ml/min; pulsation rate 90/min) or a standardized roller pump with continuous flow (30 ml/min). Ventilation was performed with physiologic room air (350 ml; 16/min) for 1 h. Pulsatile and nonpulsatile perfusion was performed in 2 groups (group NP: nonpulsatile; group P: pulsatile flow, n = 7) during reperfusion. Peak inspiratory pressure (PIP), mean pulmonary artery pressure (PAP), and oxygenation capacity (DeltaPO(2)) were continuously measured. For control of the effectiveness of the pulsatile perfusion pressure waveforms were obtained directly from the native pulmonary artery of both groups. Malondialdehyde (MDA) as a parameter for lipid peroxidation and endothelial cell damage was assessed at 10, 30 and 50 min reperfusion. At the end of the study, pulmonary water content was assessed by means of wet-to-dry ratio (W/D ratio). The tissue was further processed for microscopic analysis. RESULTS: PIP increased significantly in both groups during reperfusion. Mean PAP in both groups increased to 60 mm Hg after 20 min followed by a decrease after 60 min to 40 mm Hg. Pressure waveforms of the pulmonary artery showed sufficient pulsatility in the pulmonary vasculature with a systolic/diastolic pressure difference of 15 mm Hg whereas the pressure difference was 3-5 mm Hg in the nonpulsatile group. DeltaPO(2) was stable in groups NP and P during reperfusion (30 min: NP: 66.4 (62.2-88) mm Hg; P: 74.8 (65-81.7) mm Hg) without any statistically significant differences between the groups. MDA in group NP decreased over the reperfusion period from 6.2 (3.3-6.3) microM at 10 min to 5.2 (3.2-6.1) microM at 50 min, whereas in group P the level increased and was significantly higher after 50 min reperfusion compared to group NP [6.6 (6.1-9.2) microM at 50 min; p = 0.016]. W/D ratio was 6.7 (6.3-7.0) in group NP and 6.8 (6.3-7.6) in group P. Light microscopy evaluation showed no differences between both groups regarding severity of intra-alveolar and interstitial edema and numbers of intra-alveolar, intracapillary and interstitial granulocytes. CONCLUSION: Although effective pulsatile perfusion of the pulmonary vasculature was achieved by means of a modified roller pump, this measure obviously did not improve functional parameters nor did it significantly reduce the edema formation after 3 h ischemia in this extracorporeal lung perfusion model. The use of pulsatile perfusion is therefore not mandatory in the extracorporeal setting of a large animal lung perfusion model.

Animals↗