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Biomedical subjects

U Brandl

Publications and source records attributed to U Brandl.

32 records · Page 2Linked to original sources

The effect of L-carnitine-supplemented total parenteral nutrition on tissue amino acid concentrations in piglets.

Miniature piglets underwent total parenteral nutrition (TPN) with and without L-carnitine supplementation during a 7-day period. Thereafter the tissue amino acid concentrations of liver, heart, skeletal muscle and brain were determined and compared to those of orally fed animals. The altered tissue amino acid concentrations during TPN without carnitine returned to normal when L-carnitine was supplemented. The most striking changes of tissue concentrations showed taurine in liver, muscle and brain and ethanolamine in heart and brain. In muscle the branched-chain amino acids were increased when L-carnitine was added to the TPN regime. Ethanolamine changes were discussed with respect to the position of this amino acid in the synthesis of phospholipids. The marked decrease of brain taurine concentrations after carnitine-free TPN was accompanied by reduced values for GABA. Both the substances function as inhibitory transmitters in the brain and should be considered when seizure activity in patients with systemic carnitine deficiency is discussed.

Administration, Oral↗

[Clinical and chemical factors in kidney calculus formation in childhood. An analysis of 40 patients].

During 5 years, between 1978 and 1982, 40 patients (22 male, 18 female) aged 1 to 17 years presented with kidney stones at the Erlangen University Children's Hospital. Stone analysis showed calcium oxalate in 61%, calcium phosphate respectively magnesiumammonium phosphate in 33% and cystine in 6%. Calcium phosphate/ magnesiumammonium phosphate stone bearers were most frequently found in the first 5 years of age and showed more often urinary tract malformations, staghorn renal calculi, urinary tract infections and a higher urinary pH. Calcium oxalate stone bearers were more frequently found in patients of school age and had more often relatives with nephrolithiasis. In the group of calcium oxalate stones hypercalciuria, hyperoxaluria and hyperuricosuria were most frequently observed.

Adolescent↗

Tissue carnitine concentrations after total parenteral nutrition with and without L-carnitine supplementation.

The concentrations (mumoles/g dry weight) of total carnitine (TC), free carnitine (FC) and acylcarnitine (AC) were determined in skeletal muscle, heart, liver, kidney and brain cortex of male mini pigs (4000-5000 g) after seven days of total parenteral nutrition (TPN) with amino acids 5% (3.0g/kg/d), glucose (25g/kg/d) and lipids 20% (4g/kg/d). This regime was administered with L-carnitine supplementation (1.5 mg/kg/d; n = 7) (group 1) and without it (n = 5) (group 2). Orally alimented animals (n = 5) served as controls (group 3). (Average carnitine intake: 3 mg/d) Carnitine free TPN affected only the concentrations in muscle. TC was markedly reduced (3.6 +/- 0.8) when compared with oral controls (5.8 +/- 0.7) (p<0.01). This decrease was exclusively due to AC, whereas FC concentrations remained almost unchanged. In group 1 the concentrations of TC in skeletal muscle, heart and brain cortex were higher than in both the other groups. The increase was mainly due to AC and FC remained unchanged in heart and brain. The concentrations in liver and kidney were not affected by either carnitine free or carnitine supplemented TPN. AC, determined as described, consists almost entirely of acid soluble acetyl-carnitine, the major product of fatty acid oxidation. Since the AC concentrations were almost exclusively altered by the two TPN-regimes we conclude that the observed changes reflect regulatory changes of fatty acid oxidation. Thus the decrease of muscle TC in group 2 is considered a consequence of an insulin induced down regulation (plasma insulin: mean 20 muU/ml; maximum: 60 muU/ml) of fatty acid oxidation in consequence of high glucose intake (25 g/kg/d). The increased TC concentrations after carnitine supplemented TPN are discussed to reflect an enhancement of oxidative degradation of fatty acids as a pharmacological effect of L-carnitine.

Journal Article↗

Combining the hDAF transgene with the GP IIb/IIIa inhibitor tirofiban improves heart performance and reduces myocardial damage following hyperacute rejection in an ex vivo perfusion model.

Xenograft rejection is associated with vascular injury resulting at least in part from platelet activation, and rejected xenografts invariably demonstrate intravascular thrombosis. Assuming that complement activation is a major determinant of humoral immune reactions bringing about platelet-endothelial cell interactions, we tested the effects of the specific platelet glycoprotein IIb/IIIa inhibitor tirofiban in combination with the human decay accelerating factor (hDAF) transgene on hyperacute rejection of pig hearts. Four groups were studied in a working heart-perfusion model. Pig hearts transgenic for hDAF and nontransgenic pig hearts were perfused with human blood containing tirofiban or with unmodified human blood. Cardiac output, stroke work index, and creatine phosphokinases were measured for the evaluation of the extent of myocardial damage. Consumption of complement components was determined. Endothelial deposition of fibrin and intravascular thrombosis were evaluated. Tirofiban improved cardiac output and stroke work index of nontransgenic pig hearts and was able to further increase hemodynamic function of hDAF transgenic pig hearts. Low levels of creatine phosphokinases also revealed a cardioprotective effect of tirofiban. However, a further extension of the survival of hDAF transgenic pig hearts could not be achieved, although tirofiban prolonged beating time of nontransgenic pig hearts. Tirofiban was able to reduce the consumption of complement components independently of hDAF. Intravascular evidence of fibrin and thrombosis tended to be particularly reduced by the combination of tirofiban and hDAF. Thus, the application of tirofiban together with hDAF improves the performance of pig hearts by reducing myocardial damage and intravascular thrombosis.

Acute Disease↗

Mean xenograft survival of 14.6 days in a small group of hDAF-transgenic pig hearts transplanted orthotopically into baboons.

INTRODUCTION: In a discordant orthotopic xenotransplantation model (pig-to-baboon) donor pigs expressing human decay accelerating factor (hDAF) as a regulator of complement activity were used to prevent hyperacute xenograft rejection (HXR). We investigated a modified immunosuppressive therapy consisting of ERL080 (Novartis Pharma AG, Base, Switzerland), cyclosporin A (Neoral), steroids, and a cyclophosphamide (CyP) induction protocol with several reduced doses to prevent acute vascular rejection (AVR). METHODS: Donor hearts were harvested from hDAF-transgenic pigs (18.8 +/- 2.6 kg, Imutran Ltd., a Novartis Pharma AG Company). Four adult baboons (25.6 +/- 2.7 kg) with high titers of xenoreactive antibodies (XAb) served as recipients. Serological and hemodynamic parameters were measured. Finally, myocardial tissue was sampled for histological and immunohistochemical examinations. RESULTS: In the first baboon, an acute graft failure occurred after 1 hour due to preservation injury. The second succumbed after 11.1 day due to an acute renal failure. The third died after 13.1 days of an ileus. The fourth baboon had continuously excellent cardiac function (mean echocardiographic ejection fraction, 69.2%), but succumbed on day 20 due to anemia. Corrected mean xenograft survival (excluding the first baboon because of a technical failure) was 14.6 +/- 2.6 days. XAb decreased after day 3 to constantly low levels (<1:64 titer) after CyP induction. White blood cell count decreased from 10.3 +/- 0.8 to 0.9 +/- 0.3 G/L after day 3. Macroscopically and histologically no typical signs of HXR or severe AVR could be detected. CONCLUSIONS: These results confirm that hDAF transgen blocks HXR in this life-supporting model. AVR was prevented by using a modified quadruple immunosuppressive drug combination (Neoral, ERL080, steroids, and several small single doses of CyP). An optimum "fine-tuning" of immunosuppression is required to achieve the best risk-benefit ratio.

Animals↗

Combination of hDAF-transgenic pig hearts and immunoadsorption in heterotopic xenotransplantation of immunosuppressed baboons.

INTRODUCTION: Hyperacute xenograft rejection (HXR) and acute vascular rejection (AVR) after xenotransplantation are triggered by xenoreactive antibodies (XAb) and an activated complement cascade. In a heterotopic (abdominal) xenotransplantation model we combined immunoadsorption (IA, Ig-Therasorb column) and a quadruple immunosuppressive drug therapy in recipient baboons with donor pig hearts transgenic for human decay accelerating factor (hDAF). METHODS: According to XAb titers between 6 and 14 cycles of IA were performed preoperatively in 4 recipient baboons (18.6 +/- 2.5 kg). Hearts of hDAF-transgenic donor pigs (6.1 +/- 1.1 kg, Imutran Ltd., a Novartis Pharma AG Company, Basel, Switzerland) were heterotopically transplanted using the abdominal technique in baboons. Immunosuppression consisted of cyclophosphamide (CyP) induction therapy, ERL080 (Novartis Pharma AG), cyclosporin A (CyA, Neoral), and steroids. Blood levels of mycophenolate, CyA, immunoglobulins (Ig), anti-pig-antibodies, complement factors, and cardiac enzymes were determined. Abdominal electrocardiography (ECG), echocardiography, and palpation were used for monitoring of the pig hearts. Myocardial tissue specimens were examined using immunohistochemistry, light microscope (LM), and electron microscope (EM). RESULTS: Ten cycles of IA alone removed 78% of XAb and accordingly IgM, IgG, IgA, complement C3, and C4. None of the xenografts was hyperacutely rejected, but xenograft failure occurred after 5.0 +/- 1.3 days (range, 2.4-8.0 days) because of an AVR associated with a rapid XAb increase within 24 hours. White blood cell count (10.3 +/- 2.2 G/L) showed a maximum of 13.1 +/- 2.1 (day 1) and constant levels (1.4 +/- 0.3-2.1 +/- 1.3 G/L) between day 3 and 6. Histology (LM/EM) showed massive hemorrhage, necrosis, and vascular thrombi as signs of AVR. CONCLUSION: Although HXR was prevented by using IA and hDAF-transgenic donor hearts, AVR was not avoided due to insufficient immunosuppressive regimen used and a missed postoperative IA treatment as a result of an inefficient control of XAb production.

Adrenal Cortex Hormones↗

[Optimizing epilepsy therapy in children and adolescents with lamotrigine].

Lamotrigine is a broadly effective antiepileptic drug in mono- and add-on therapy for children and adolescents with focal and generalized epilepsies. Some epileptologists consider lamotrigine as the drug of primary choice in older school children and adolescents because of its good tolerability (no increase of body weight, no impairment of cognitive functions, due to new data probably no teratogenic properties). Lamotrigine can be used with good efficacy in numerable epilepsy diseases, such as tuberous sclerosis, juvenile neuronal lipofuscinosis and Rett syndrome. The first studies show that lamotrigine is also effective in children under 2 years of age. For therapy of difficult-to-treat epilepsies the combination of lamotrigine with valproate has proved as especially useful. This clinical observation is supported by new results of animal experiments. The dose-dependant and typical CNS side effects vertigo, ataxia, nausea, tremor and diplopia are found most frequently. The rate of allergic skin rashes which was very high before 1998 has decreased markedly by new dosage guidelines and is now as low as in older antiepileptic drugs. Lamotrigine does not impair cognitive functions, especially not memory and language. It has mood-stabilizing features and may improve quality of life. In animal experiments lamotrigine shows antiepileptogenic and neuroprotective effects.

Adolescent↗

[Doppler sonographic flow parameter of the anterior cerebral artery in patent ductus arteriosus of the newborn infant compared to a healthy control sample].

33 premature infants (age: 32 +/- 3 weeks; birth weight 1,268 +/- 535 gs) with the clinical signs of patent ductus arteriosus Botalli (PDA) and a control group of 96 healthy infants (age: 37 +/- 4 weeks; birth weight 2 348 +/- 944 gs) were investigated. Pulsed doppler recordings were obtained in the anterior cerebral arteries (ACA) and compared with the flow pattern in the truncus coeliacus (TC). In all children the maximal systolic velocity (Vs), the endsystolic (Ves) and the enddiastolic velocity (Ved) and the pulsatility-index (PI) were measured. The 96 healthy premature born infants showed the following velocities: Vs: 41 +/- 12 cm X sec-1; Ves: 19 +/- 7 cm X sec-1; Ved: 10 +/- 4 cm X sec-1. The pulsatility-index was 0.74 +/- 0.08. In children with PDA all velocities were significantly lower than in the healthy control group: Vs: 31 +/- 10 cm X sec-1; Ves: 7 +/- 6 cm X sec-1; Ved: -1 +/- 5 cm X sec-1. Ved was more decreased than Vs resulting in a significant increase in PI (1.04 +/- 0.14). 22 infants with surgically proven large PDA (age: 31 +/- 3 weeks; birth weight: 1,160 +/- 467 gs) showed significant lower velocities (Vs: 34 +/- 8 cm X sec-1; Ves: 4 +/- 4 cm X sec-1; Ved: -4 +/- 4 cm X sec-1) in comparison with the healthy control group and the 11 children with small PDA (age: 33 +/- 4 weeks; birth weight: 1,494 +/- 621 gs).(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗

Visuomotor coordination during focal and generalized EEG discharges.

A new computer-based method for continuous gauging of momentary, visuomotor coordination under simultaneous EEG control proved both effective and suitable for children. Thirty-eight patients (age 4-17 years) who had different types of hypersynchronous activity were examined: None of the patients with focal discharges showed significant impairment in the test performance. Slight losses were evident in less than 3-s generalized, irregular spike-wave paroxysms. Deterioration was particularly evident in the bilateral synchronous 3-Hz spike-wave series, which lasted greater than 3 s.

Adolescent↗

Bridging to transplant: allogeneic heart transplantation after xenografting.

Xenografting seems to be a solution to use to bridge time intervals when desperately needed allograft cannot be obtained. A following allograft was never ventured. Nine dogs (weight, 20 to 25 kg; age, 2 years) underwent right cervical heart transplantation. Donors were silver foxes (3 to 4 kg). The animals were treated by triple-drug therapy consisting of cyclosporine, methylprednisolone, and azathioprine in clinical dosages. For control, six recipients received only allogeneic hearts and the identical immunosuppression. After rejection of the xenograft, a second allogeneic heart was anastomosed subsequently to the same right cervical vessels. Routine histologic and immunohistologic examinations were performed. Thromboxane B2 and 6-keto-prostaglandin F1 alpha were determined daily in peripheral blood. After final rejection the sensitization of the recipient was controlled by hemagglutination test. Survival time of the xenografts was 9.6 +/- 1.2 days; the subsequent allogeneic hearts under the same therapy beat for 4.5 +/- 5.0 days. The average survival time of control hearts was 18 +/- 1.9 days. The five hyperacute second allografts showed signs of humoral rejection by absence of inflammation. The release of thromboxane B2 was different in hyperacute, accelerated, or cellular rejection. In contrast to the long-functioning grafts, thromboxane B2 persisted during hyperacute rejection at a high level. However, 6-keto-prostaglandin F1 alpha showed no significant differences between longtime survivors and hyperacute rejecting hearts. After xenogeneic transplantation, all recipients showed hemagglutinating titers between 1:4 and 1:16. Allogeneic grafts have a different kinetics of rejection after xenogeneic heart transplantation compared with control hearts. Thromboxane B2 seems to be an important mediator in hyperacute rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗

Noninvasive methods of rejection diagnosis after heart transplantation.

For clinical follow-up and prognosis in heart transplant patients, it is important to understand accurately the presence and extent of cardiac allograft rejection. Since the introduction of endomyocardial biopsy, almost 40 different noninvasive diagnostic procedures for the recognition of myocardial rejection have been proposed. However, endomyocardial biopsy is invasive and not suitable for frequent monitoring. If the pattern of rejection shows a focal distribution, false-negative results can be expected. Discrepancies between biopsy findings and allograft function are obviously possible. State-of-the-art information will be given on the most reliable noninvasive methods for rejection diagnosis, which can be differentiated from electrophysiology (fast-Fourier-transformed electrocardiography and intramyocardial electrocardiography), echocardiography, immunologic methods (cytoimmunologic monitoring, transferrin receptors, and interleukin-2 receptors), various biochemical markers (neopterines, prolactin, urinary polyamines, and beta 2-microglobulins), radioisotopic techniques (antimyosin-monoclonal antibodies, thallium, technetium, and gallium scintigraphy and indium-labeled cells), as well as magnetic resonance imaging. Thus modified and patient-adapted antirejection therapy can be provided if the decision for or against antirejection therapy is not based on biopsy findings alone but rather is confirmed along with histologic, electrophysiologic, biochemical, immunologic, and functional parameters.

Diagnostic Imaging↗

Kinetics and dynamics of acute rejection after heterotopic heart transplantation.

Right cervical, heterotopic heart transplantation was performed in 18 mongrel dogs. Study design was based on three different groups (n = 3 x 6). Standard immunosuppression consisted of triple drug therapy in all dogs. Groups II and III received high dose steroids during acute rejection. In group III the native hearts of previous recipients (groups I and II) were used as donors for heterotopic transplantation ("domino" principle). The hearts were examined by daily transmural biventricular biopsies and graded according to Billingham classification. Cytoimmunologic monitoring (n = 345; activation index from peripheral and coronary sinus blood) and fast Fourier transformation ECG (n = 80; area under the curve; surface recordings) served as daily noninvasive methods. Optionally antimyosin scintigraphy (n = 25; single photon emission computed tomography; heart-to-lung ratio) was performed and immunohistologically confirmed by peroxidase staining of the antibody (n = 61). Kinetics of rejection was not uniform in group I (onset after 5.7 days) and biphasic in group II (clear rejection-free interval: 6.8 days). Group III developed a continuously persisting rejection, despite repeated high-dose steroids, with an early onset (3.2 days). The invasive data, consisting of 587 punch biopsies, showed no significant difference between right and left ventricular rejection. Clearly focal rejection appeared in 51.5% of the cases, with subendocardial involvement in 54%. Cytoimmunologic monitoring significantly (p less than 0.001) correlated with daily biopsies in groups I and II. The activation index from coronary sinus blood was two times higher than in peripheral blood. Fast Fourier transform ECG identified the onset of rejection with great accuracy (p less than 0.01). The heart-to-lung ratio of antimyosin scintigraphy corresponded exactly to the various stages of rejection (p less than 0.001). High-dose steroids led to a clear reduction of the ratio in 26% cases. Peroxidase staining showed typical locations of the antibody, depending on the grade of rejection (p less than 0.001). Considering the results of pathology in this transplantation model, relying on endomyocardial biopsy alone in a clinical setting may not seem advisable. Although the results of this study must be confirmed clinically, the simultaneous use of cytoimmunologic monitoring and fast Fourier transformation ECG may prove to be valuable to day-to-day monitoring for acute rejection in the early postoperative course. If both methods indicate the onset of an acute rejection, antimyosin scintigraphy and endomyocardial biopsy, respectively, should be performed to confirm and grade the suspected diagnosis.

Animals↗