Stimulation of rat hepatic amino acid transport by burn injury

Burn injury accelerates hepatic amino acid metabolism, but the role of transmembrane substrate delivery in this response has not been investigated. We therefore studied the effects of cutaneous scald injury on the Na+-dependent transport of glutamine and alanine in isolated rat liver plasma membrane vesicles. Scald injury resulted in liver damage and a 1.4- to 2.3-fold and 1.5- to 2.8-fold stimulation of hepatic transport rates for glutamine and alanine, respectively, proportional to the total burned surface area (TBSA) after 24 hours. Enhanced uptake of glutamine and alanine was attributable to increases in the maximum velocity (Vmax) of system N and system A activities, respectively. Hepatic amino acid transport activity remained elevated in vesicles from burned animals after 72 hours, but the degree of stimulation (1.3- to 1.7-fold for glutamine and 1.3- to 1.6-fold for alanine) was less than that observed 24 hours after thermal injury. Liver function tests returned to control values after 72 hours as well, indicating rectification of hepatic damage. In contrast to the induction of hepatic system A and system N activity in catabolic states such as cancer and endotoxemia, further studies showed that tumor necrosis factor (TNF) failed to play a significant role in burn-stimulated amino acid transport rates. When combined with plasma liver enzyme profiles, early transient hepatic amino acid transporter stimulation may support amino acid-dependent pathways involved in the repair of burn-dependent hepatic damage.

Mapping of the ligand-selective domain of the Xenopus laevis corticotropin-releasing factor receptor 1: implications for the ligand-binding site

The nonselective human corticotropin-releasing factor receptor 1 (hCRF-R1) and the ligand-selective Xenopus CRF-R1 (xCRF-R1) were compared. To understand the interactions of sauvagine and ovine CRF, both high-affinity ligands for hCRF-R1 but surprisingly weak ligands for xCRF-R1, chimeric receptors of hCRF-R1 and xCRF-R1 followed by double or multiple point mutations were constructed. Binding studies and cAMP assays demonstrated that the N-terminal domain exhibited the complete ligand selectivity of xCRF-R1. The important region was mapped between amino acids 70 and 89; replacement of amino acids Arg76, Asn81, Gly83, Leu88, and Ala89 in hCRF-R1 with the corresponding amino acids of xCRF-R1 (Gln76, Gly81, Val83, His88, and Leu89) resulted in a receptor that had approximately 30-fold higher affinity for human/rat CRF than for sauvagine. Mutagenesis of these amino acids in xCRF-R1 to the human sequence completely abolished the ligand selectivity of xCRF-R1. Mutagenesis of amino acids 88 and 89 in hCRF-R1 or xCRF-R1 had only a minor (approximately 2.5-fold) effect on the ligand selectivity of the mutant receptor. Substitution of Arg76, Asn81, and Gly83 in hCRF-R1 with the corresponding sequence of xCRF-R1 (Gln76, Gly81, and Val83) resulted in a receptor with approximately 11-fold higher affinity for human/rat CRF compared with ovine CRF or sauvagine. When only two of these three amino acids were mutated, no effect on the ligand selectivity was observed. On the basis of these data, it is suggested that amino acids 70-89 of CRF-R1 are important for the ligand binding site.

Pain, coping and psychological well-being in late life

In the present article, the relationships between pain, coping, functional capacity and psychological well-being are examined in a population of older patients (>/=60 years; n=202) treated for a variety of somatic complaints in a university-affiliated hospital. Results indicate that moderate to extreme pain is common in older patients and often occurs in several body regions simultaneously. Extreme pain in one or more body regions is associated with reduced daily functional capacity, lower values for life satisfaction and self-evaluated competence, and more negative attitudes towards the present and future. Results of a hierarchical cluster analysis reveal interindividual differences in coping approaches among older patients suffering from extreme pain; they also emphasize the importance of cognitive strategies and life-review coping. Relevance for clinical practice with older pain patients is discussed.In the present article, the relationships between pain, coping, functional capacity and psychological well-being are examined in a population of older patients (>/=60 years; n=202) treated for a variety of somatic complaints in a university-affiliated hospital. Results indicate that moderate to extreme pain is common in older patients and often occurs in several body regions simultaneously. Extreme pain in one or more body regions is associated with reduced daily functional capacity, lower values for life satisfaction and self-evaluated competence, and more negative attitudes towards the present and future. Results of a hierarchical cluster analysis reveal interindividual differences in coping approaches among older patients suffering from extreme pain; they also emphasize the importance of cognitive strategies and life-review coping. Relevance for clinical practice with older pain patients is discussed. Copyright 1998 European Federation of Chapters of the International Association for the Study of Pain.

Biographical reconstruction of WWII experience: an exploration of German remembrance

First results of the Eldermensch-Study (N = 50) indicate that German National Socialism and the historical events associated with World War II play a central role in the oral histories of older Germans. Six distinct patterns of late life cognitive appraisal of war-time experience: survival challenge (further divided into "active" and "passive" survivorship), passive benefit, opportunism, value verification, and acceptance despite hardship are presented and discussed as structural themes in the life story. These categories not only represent interindividual differences in the appraisal of war-time experience, but often reflect contrasting patterns of personal response to the social and political circumstances of this era of German history. In addition to cohort and gender differences, divergence in locus of control orientation as well as the role of social bonding and instrumental social support are discussed. Differences revealed in the biographical interviews are further reflected in the results of standardized questionnaires.

A prospective randomized trial comparing interleukin-2 receptor antibody versus antithymocyte globulin as part of a quadruple immunosuppressive induction therapy following orthotopic liver transplantation

BACKGROUND

Quadruple immunosuppressive induction therapy has been shown to markedly reduce the incidence of acute rejection episodes without increasing the incidence of infectious complications after liver transplantation. However, the use of polyclonal antibody preparations (e.g. antithymocyte globulin [ATG]) is associated with side effects such as fever and tachycardia. To evaluate the efficacy and the safety of a monoclonal antibody directed against the interleukin-2 receptor (BT563) in comparison with ATG as part of a quadruple induction regimen, a prospective, randomized study was conducted.

METHODS

Eighty consecutive adult recipients of primary orthotopic liver transplants were randomized to receive either BT563 (10 mg/day; days 0-12; n=39) or ATG (5 mg/kg/day; days 0-6; n=41) in addition to the standard immunosuppressive protocol consisting of cyclosporine, and prednisolone, and azathioprine.

RESULTS

Patients treated with BT563 had a significantly lower incidence of steroid-sensitive rejection episodes (3 vs. 11; P<0.025) and also significantly fewer drug-related side effects (4 vs. 18, P<0.038) when compared with patients treated with ATG. The incidence of infectious complications was not different between the two groups. Patient survival did not differ significantly between the two groups (84.6% at 1, 2, and 3 years in the BT563 group and 90.2% at 1 year and 87.8% at 2 and 3 years for the ATG group). Analysis of graft function showed an advantage for the BT563 group in terms of postoperative bilirubin levels. However, no differences were observed in long-term follow-up between the two groups.

CONCLUSIONS

Our results indicate that treatment with anti-interleukin-2 receptor antibody as part of quadruple induction therapy after orthotopic liver transplantation is safe and effective and shows fewer steroid-sensitive rejection episodes as well as fewer side effects when compared with quadruple induction therapy including ATG.

Induction of glutamine synthetase expression after major burn injury is tissue specific and temporally variable

BACKGROUND

Major burn injury results in a translocation of amino acids from peripheral tissues to the abdominal viscera. Glutamine is a major participant in this event. Thermal injury causes a depletion of plasma and muscle glutamine pools as well as activation of proteolysis and release of glutamine from skeletal muscle. De novo synthesis of glutamine is regulated by the expression of the enzyme glutamine synthetase (GS). We studied the tissue-specific regulation of GS expression after thermal injury.

METHODS

Burn injury of rats was produced by scalding of 25 or 40% of skin surface. In normal rats, four organs, including lung, muscle, kidney, and liver were assayed for relative GS messenger RNA content by Northern blotting 8 and 24 hours after 40% area burn. The effect of adrenalectomy on GS mRNA induction in muscle was assessed 24 hours after 25% area burn injury.

RESULTS

GS mRNA levels were increased 2.3-fold in lung at 8 hours and 7.3-fold in muscle at 24 hours after burn injury. No appreciable increase in GS mRNA level was observed in kidney or liver. Muscle GS mRNA levels were lower than sham-operated controls in both burned and unburned adrenalectomized rats. However, adrenalectomy did not attenuate relative GS mRNA induction in muscle at 24 hours after burn injury.

CONCLUSIONS

Burn injury causes an induction in GS mRNA levels in a tissue-specific fashion. Adrenalectomy greatly reduced GS mRNA levels, but did not completely block the induction of GS express in muscle after burn injury. This finding suggests that glucocorticoid hormones together with a unknown factor of nonadrenal origin influence this metabolic response to burn injury.

A prospective study of human herpesvirus type 6 detected by polymerase chain reaction after liver transplantation

Human herpesvirus type 6 (HHV-6) causes roseola infantum (exanthema subitum) upon primary infection in young children. Thereafter it persists lifelong in the organism. Like other herpesviruses, HHV-6 can be reactivated in periods of immunosuppression - e.g., after organ transplantation. In order to study the incidence and the time to reactivation after orthotopic liver transplantation (OLT) we tested buffy coat lysates before and up to 10 weeks after transplantation for the presence of HHV-6 DNA by polymerase chain reaction (PCR). Forty-six patients (male n=27, female n=19) with a median age of 48 years (range 20-66) were studied. Altogether, 30 of 287 (10.5%) buffy coat samples were PCR-positive. Before OLT 2 of 21 (9.5%) patients were positive. This ratio is not different from healthy blood donor controls. After OLT 13 of 46 (23.8%) patients were positive on one or more occasions. However, there was no statistically significant difference before and after OLT. Ten patients were analyzed for HHV-6 variants by restriction enzyme digestion of PCR products. One patient carried variant A and 9 variant B. In conclusion, HHV-6 can be detected in buffy coat cells after OLT. Our observations do not argue in favor of a reactivation.

Structure optimization of an artificial neural filter detecting membrane-spanning amino acid sequences

An artificial neural network has been developed for the recognition and prediction of transmembrane regions in the amino acid sequences of human integral membrane proteins. It provides an additional prediction method besides the common hydrophobicity analysis by statistical means. Membrane/nonmembrane transition regions are predicted with 92% accuracy in both training and independent test data. The method used for the development of the neural filter is the algorithm of structure evolution. It subjects both the architecture and parameters of the system to a systematical optimization process and carries out local search in the respective structure and parameter spaces. The training technique of incomplete induction as part of the structure evolution provides for a comparatively general solution of the problem that is described by input-output relations only. Seven physiochemical side-chain properties were used to encode the amino acid sequences. It was found that geometric parameters like side-chain volume, bulkiness, or surface area are of minor importance. The properties polarity, refractivity, and hydrophobicity, however, turned out to support feature extraction. It is concluded that membrane transition regions in proteins are encoded in sequences as a characteristic feature based on the respective side-chain properties. The method of structure evolution is described in detail for this particular application and suggestions for further development of amino acid sequence filters are made.

Rejection episodes after liver transplantation during primary immunosuppression with FK506 or a cyclosporine-based regimen: a controlled, prospective, randomized trial

As part of a European multicenter study to investigate the potency of FK506 in primary immunosuppression after liver transplantation, this comparison with our conventional cyclosporine-based quadruple regimen was carried out as a controlled, prospective, randomized trial. The 121 patients entering the study were randomly assigned to receive immunosuppressive regimens consisting either of FK506 and prednisolone (FK/n = 61) or of cyclosporine, prednisolone, azathioprine, and a 7-day course of rabbit antithymocyte globulin (CsA/n = 60). Rejection was suspected in the case of scant production of light bile or biochemical graft dysfunction, without evidence of vascular, biliary, or infectious complications. A liver biopsy for confirmation of the diagnosis was obtained each time. Initial therapy entailed a 3-d course of high-dose methyl-prednisolone. Steroid resistant rejections were treated with OKT3 monoclonal antibody or, in the group of primary CsA administration, conversion to FK506 as another treatment option. One-year patient (FK: 90.2%; CsA: 96.7%) and graft survival (FK: 88.5%; CsA: 91.7%) did not differ significantly. Overall, 41 patients (33.9%) experienced 50 acute, cellular rejection episodes (RE) [FK: 25 RE in 21 patients (34.4%); CsA: 25 RE in 20 patients (33.3%)]. The histological grading ranged from mild (FK: 14/25; CsA: 8/25) to moderate (FK: 9/25; CsA: 16/25) and severe (FK: 2/25; CsA: 1/25): not significantly different between the two groups. In the CsA-based group, three additional rejection episodes were classified as early chronic (n = 1) and chronic rejection (n = 2).(ABSTRACT TRUNCATED AT 250 WORDS)

P-glycoprotein expression in chronic lymphocytic-leukemia - association with chemotherapy

P-glycoprotein (PgP), a transmembrane protein, has been associated with multiple drug resistance. We examined 42 patients with chronic lymphocytic leukemia immunohistochemically using the monoclonal antibody JSB-1 to determine the prevalence of PgP expression and its relationship with chemotherapy exposure. Of the 42 patients, 31 (74%) had detectable PgP. No relationship was found between PgP expression, patient age, duration of disease or stage. Moderate and strong intensity staining was found in 22% of untreated patients versus 56% patients treated with chemotherapy (p<0.05). Temporal fluctuations in P-glycoprotein staining intensity was seen in 6 of 7 cases which paralleled the initiation or withdrawal of the therapy.

[Psychosomatic aspects of pain perception by the elderly--results of the ELDERMEN Study]

115 geriatric in-patients are included in the current study examining relationships between regions of experienced pain, subjective pain intensity, and psychological variables. An investigation of the connection between psychosomatic limitations (BSS) and pain indicated, that pain patients do not necessarily require psychosomatic-psychotherapeutic treatment (in our study only 21.6%). 61.7% of the study sample reported intense pain at least one body region. These patients differed significantly from those with less pain in terms of their level of functional capacity and need for assistance in daily activities (ADL/IADL). They also displayed a significantly more negative attitude towards aging (PGC) than patients with minimal pain. Hierarchical cluster analyses for applied coping strategies produced five groups within the subgroup of patients suffering from extreme pain. Only within one group "depression" was a significant reaction to health-problems. These results make clear that most of the patients with extreme pain are able to cope effectively with pain.

[Life review: promoting the developmental potentials in aging]

In this paper the theoretical background and practical applications of the life review are discussed. Particular emphasis is placed on the relevance of the life review for the mastery of developmental transitions across the entire life span as well as for adaptation to the challenges commonly associated with aging. The terms guided autobiography, life review and reminiscence are explained as are techniques for guiding reminiscence and life review. The life review is presented as a method which can be effectively used in community or institutional settings.

[Radioisomorphisms of sclerosing cholangitis]

For differentiation of Primary Sclerosing Cholangitis (PSC) from AIDS-associated cholangitis (AAC), 95 CT or Cholangiography studies of 37 patients were reviewed and signs of biliary disease analysed. Only two each of PSC and AIDS-subjects were free from biliary lesions compatible with some kind of sclerosing cholangitis. Subgroup analysis revealed wide overlapping of morphological findings in PSC and AAC. We conclude that radioisomorphism of etiologically different forms of sclerosing cholangitis may indicate pathophysiologically similar courses.

Mycobacterial infection after liver transplantation

Tuberculosis occurred in 5 (1.2%) of 462 liver transplant recipients. De novo infection was assumed in 4 patients and a recurrent infection in 1. The clinical courses varied, from asymptomatic open lung tuberculosis to disseminated disease with cerebral tuberculoma and convulsions. Four patients survived with anti-tuberculous triple-drug therapy. Very few cases of tuberculosis after liver transplantation have been reported (4 patients in the medical literature and 5 patients in this paper). However, the incidence, course of infection, and outcome seem to be similar to those of tuberculosis in renal transplant recipients, approximately 150 cases of which are known.

Comparison of polymerase chain reaction from plasma and buffy coat with antigen detection and occurrence of immunoglobulin M for the demonstration of cytomegalovirus infection after liver transplantation

We compared the value of PCR on plasma with PCR on buffy coat leukocytes, Ag assay, and the determination of IgM antibodies by ELISA for the diagnosis and follow-up of cytomegalovirus infection. Thirty patients were followed after liver transplantation (LTX). We compared the tests to assess their clinical usefulness. Fourteen of 30 (46%) patients were both positive in plasma and buffy coat PCR and Ag test. Sixteen patients were negative in both procedures. There was a 97.2% concordance between PCRs done from plasma or buffy coat. The concordance of results of PCR and Ag test in single samples was 94.3%. Discordant results were found in 5.6% of samples. Discordance was observed in the early and the late phase of CMV infection and was due to positive PCRs preceding positive Ag tests for 1-3 weeks in one-half of the patients. IgM antibodies were first observed after a median period of 8 weeks (range, 6-11 weeks) after LTX. Positive PCRs and Ag tests preceded clinical manifestation of CMV disease by a 1 week median (range, 0-3 weeks), whereas positive IgM ELISAs occurred after a median period of 2.5 weeks (range, 0-4 weeks) after the onset of CMV disease. The sensitivity and specificity of both PCR and Ag test were identical, 100% and 76%, respectively. However, for the IgM ELISA, the sensitivity was only 66%, and the specificity was 84%. In conclusion, plasma or buffy coat PCR and Ag test are equally reliable procedures for early detection and monitoring of CMV infection. PCR can become positive earlier than the Ag test, but it is technically more demanding to perform. The demonstration of IgM antibodies is of little practical help because an antibody response occurs too late in relation to infection.