Analysis of glucocorticoid and mineralocorticoid signalling by gene targeting

To get a better understanding of the role of glucocorticoid and mineralocorticoid signalling during development and in whole animal physiology, we have disrupted the mouse glucocorticoid and mineralocorticoid receptor gene by gene targeting. Most of the mice with a disrupted glucocorticoid receptor gene die within the first hours after birth due to severe lung atelectasis. Perinatal induction of gluconeogenic enzymes in the liver is impaired. Feed back control of the glucocorticoid synthesis via the hypothalamic-pituitary-adrenal axis is perturbed leading to increased plasma levels of corticosterone and adrenocorticotrophic hormone. Increased activity of the hypothalamic-pituitary-adrenal axis results in extensive hypertrophy and hyperplasia of the cortical zones of the adrenal and induction of genes involved in steroid biosynthesis. The adrenal medulla is disorganized and severely reduced in size; cells capable of adrenaline synthesis are missing. Mineralocorticoid receptor deficient mice die around day 10 after birth. Weight loss precedes death of homozygous mutant mice and is correlated with an increase in the haematocrit. As a consequence of this mutation plasma levels of renin, angiotensin II, and aldosterone are highly elevated.

Decreasing period-length of the endogenous circadian rhythm of oxygen evolution in Acetabularia and its possible relation to aging

Endogenous circadian rhythms observed under constant conditions normally show period length variations. However, a general trend is difficult to identify when cells or organisms are entrained with the usual 24-h-period light/dark cycles. Therefore, these variations in time have been considered as fluctuations. In order to gain more insight into this phenomenon, individual Acetabularia cells were exposed to light/dark cycles of 16 h (LD 8:8) and 33.6 h (LD 16.8:16.8), respectively, i.e., periods which lie distinctly outside the range of the normal circadian entrainment. Employing a high-resolution procedure for data analysis, decreasing period lengths could consistently be detected when cells were kept under constant conditions for several weeks. Possible causes of this decrease are discussed.

O-glycosylation of fibrinogen from different mammalian species as revealed by the binding of Escherichia coli biotinylated lectins

After the demonstration that neither N-glycans nor neuraminic acid are involved in the binding of K88 lectins to the B beta and gamma chains of porcine fibrinogen and that their recognition was due to O-glycans (L'Hôte C, Berger S, Bourgerie S, Duval-Ifiah Y, Julien R, Karamanos Y. Infect Immun 1995; 63: 1927-1932) it clearly appeared that these lectins could be used as probes to detect O-glycans on fibrinogens of other species. The conclusion of the present study is that many mammalian fibrinogens contain complex O-glycans on B beta and gamma chains. In addition, the combined use of the biotinylated K99 lectin and the Peanut agglutinin demonstrated the presence of sialylated T-antigens on the A alpha chains of all the fibrinogens examined. These lectins can now be used to determine differences on the glycosylation status of fibrinogens within one species and also to detect O-glycans on other glycoproteins.

Aprotinin improves outcome of single-ventricle palliation

BACKGROUND

Elevation of pulmonary vascular resistance as a consequence of cardiopulmonary bypass may lead to failure of single-ventricle palliation. We reviewed our experience with aprotinin, a nonspecific serine protease inhibitor, to determine whether it could ameliorate the inflammatory effects of cardiopulmonary bypass and improve outcome of single-ventricle palliation.

METHODS

Forty-six consecutive patients undergoing single-ventricle palliation using cardiopulmonary bypass were reviewed retrospectively. Aprotinin was used in 8 of 30 bidirectional cavopulmonary shunt and 10 of 16 Fontan procedures.

RESULTS

Aprotinin use was associated with a decrease in the early postoperative transpulmonary gradient among patients undergoing Fontan and bidirectional cavopulmonary shunt procedures. The bidirectional cavopulmonary shunt aprotinin group had a higher oxygen saturation and a decrease in quantity and duration of thoracic drainage. Among patients receiving aprotinin there were no episodes of mediastinitis, thrombus formation, or renal failure.

CONCLUSIONS

Aprotinin use in single-ventricle palliation was associated with decreased transpulmonary gradient and increased oxygen saturation consistent with decreased pulmonary vascular resistance. This retrospective study suggests that aprotinin has a favorable impact on the early postoperative course of single-ventricle palliation.

Statistical approach for evolutionary relationship of alpha-conotoxins and members of insulin-superfamily

Similar conserved structures appear in apparently unrelated protein families. Thus, the superfamily of insulin shows an evolutionary relationship with the alpha-conotoxins of marine fish-hunting snails as indicated by methods of protein comparison. In order to reach statistical significance, the A-chains of different insulins, insulin-like growth factors, relaxins, insulin related peptides from invertebrates were drawn for comparison. These data were correlated with sequences from randomly chosen proteins. The alpha-conotoxins show identity scores up to 37.5% and similarity up to 56.2% toward the members of the insulin-superfamily. These scores conform to values achieved by comparing the relaxin and the insulin/IGF-sequences. The data show clearly that the identity and similarity values obtained in the comparison with the insulins are significantly higher than the scores of randomly chosen protein primary structures. According to our calculated data, this hormone system regulating metabolism and growth in vertebrates and the mentioned toxin-receptor system share the same evolutionary ancestor. However, this statistical approach has to be substantiated on gene level.

Regulation of De-N-Glycosylation Enzymes in Germinating Radish Seeds

The activities of the de-N-glycosylation enzymes endo-N-acetyl- [beta]-D-glucosaminidase (ENGase; EC 3.2.1.96) and peptide-N4- (N-acetyl-[beta]-D-glucosaminyl) asparagine amidase (PNGase; EC 3.5.1.52) were monitored during germination and postgerminative development in radish (Raphanus sativus L. cv Flamboyant). The ENGase activity was detected only during postgermination, whereas the PNGase activity was present at high levels in both stages. When germination was inhibited with abscisic acid or cycloheximide, PNGase activity was detected at a basic level and ENGase activity was not detected at all. PNGase is present as an active protein in dry seeds and is apparently synthesized during seed formation. Conversely, the absence of ENGase in dry seeds suggests that its activity is dependent on the protein synthesis that occurs during and after germination. Treatment with gibberellic acid confirmed the production of both de-N-glycosylation enzymes after germination, and demonstrated a temporal delay between the production of the two enzymes during this period. Our results suggest that the two de-N-glycosylation enzymes are differentially regulated during plant development.

Twenty-year experience with repair of complete atrioventricular septal defects

BACKGROUND

To determine factors predicting mortality and morbidity after repair of complete atrioventricular septal defect, we retrospectively analyzed preoperative, operative, and postrepair factors on the outcome of 115 consecutive complete atrioventricular septal defect repairs at The Children's Hospital of Wisconsin between January 1974 and December 1993.

METHODS

For the entire experience the operative mortality was 13.9% (16 patients). During the most recent era, January 1988 to December 1993, operative mortality was 3.6% (2 of 55 patients). This was significantly improved from the two previous eras, January 1974 to December 1980, 28% (7 of 25) and January 1981 to December 1987, 20% (7 of 35 patients) (p = 0.02). There were seven late deaths; 10-year actuarial survival, including operative mortality was 81%. Age at complete repair decreased; before 1982 all patients were more than 12 months of age, whereas after 1982 64% (56 of 88 patients) were 12 months of age or less.

RESULTS

Moderate or severe preoperative left atrioventricular valve regurgitation was not a risk factor for operative mortality. For operative survivors with moderate to severe preoperative left atrioventricular valve regurgitation (n = 17), late postoperative left atrioventricular valve regurgitation (follow-up data available on 15 patients) was significantly reduced (severe = 1, moderate = 5, mild = 9; p = 0.007).

CONCLUSIONS

Early mortality was predicted by the era of surgical repair. Conversion to routine repair during infancy was achieved with a simultaneous decrease in operative mortality. For patients with moderate to severe preoperative left atrioventricular valve regurgitation, significant improvement in the degree of left atrioventricular valve regurgitation can be expected without an increase in operative or late mortality or morbidity.

Two Methyl Jasmonate-Insensitive Mutants Show Altered Expression of AtVsp in Response to Methyl Jasmonate and Wounding

Jasmonates are plant signal molecules that are derived from lipids through the action of lipoxygenase. Jasmonates regulate gene expression during plant development and in response to water deficit, wounding, and pathogen elicitors. The signal transduction chain that mediates jasmonate action was investigated by isolating and studying two methyl jasmonate (MeJA)-insensitive mutants of Arabidopsis thaliana. The recessive mutants, jin1 and jin4, are nonallelic and neither corresponds to coi1, a previously identified MeJA-insensitive mutant. Both mutants showed reduced sensitivity to MeJA-mediated root growth inhibition as well as reduced MeJA induction of AtVsp in leaves. Expression of AtVsp in flowers was not altered in the mutants. Furthermore, MeJA modulation of the jasmonate-responsive lipoxygenase and phenylalanine ammonia lyase genes was not altered in the mutants. jin4 plants exhibited increased sensitivity to abscisic acid in seed germination assays, whereas jin1 plants showed wild-type sensitivity. Neither mutant showed altered sensitivity to ethylene in hypocotyl growth inhibition assays. jin1 and jin4 identify genes that modulate the response of AtVsp to MeJA in leaves of A. thaliana.

Immune complex-induced interleukin-6, interleukin-10 and prostaglandin secretion by human monocytes: a network of pro- and anti-inflammatory cytokines dependent on the antigen:antibody ratio

We have used two experimental models of immune complexes to study the secretion of interleukin (IL)-10, IL-6 and their connection with the immune complex-induced synthesis of prostaglandin (PG) E2 by human monocytes in vitro. Immune complexes formed of tetanus toxoid and polyclonal anti-tetanus toxoid antiserum as well as heat-aggregated human serum immunoglobulins induced the release of IL-6 and IL-10 in a dose- and antigen: antibody ratio-dependent manner. Antigen-antibody complexes formed near equivalence were most effective in induction of a cytokine response. PGE2 could augment the immune complex-induced IL-6 and IL-10 secretion, but alone, did not induce cytokine secretion. IL-10 was capable of down-regulating the release of IL-6 and PGE2. Additionally, we demonstrated that endogenously synthesized IL-10 limited the immune complex-induced secretion of proinflammatory cytokines tumor necrosis factor-alpha and IL-1 beta. All three regulatory factors examined here share anti-inflammatory properties and are closely associated with the T helper type 2 (Th2) immune response. We conclude that immune complexes, besides their well-known ability no cause acute and chronic inflammation, can mediate immunosuppressive effects and influence the balance of Th1/Th2 responses.

Hearing loss and leukocytosis

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Distinct antigen-induced cytokine pattern upon stimulation with antibody-complexed antigen consistent with a Th1-->Th2-shift

The consequences of complexing an antigen with specific antibodies upon the antigen-induced immune response were studied with respect to secretion of interleukin-2 (IL2), interleukin-6 (IL6), interleukin-10 (IL10) and interferon-gamma (IFN gamma). We found that the tetanus toxoid antigen-induced cytokine pattern was mainly dependent on the antigen/antibody ratio. While tetanus toxoid antigen alone induced a typical Th1-like cytokine pattern with high levels of IL2 and IFN gamma, equivalent or antibody-excess immune complexes induced a marked secretion of IL6 and IL10 while failing to induce IL2 and IFN gamma secretion. As the cytokine pattern plays a crucial role in the development of specific immune responses towards infectious agents, our results indicate that immune complexes--typically occurring during the course of chronic infectious diseases--may play an important role in the modulation of immune responses. Since a shift from Th1 to Th2 immune responses has been discussed as a pathogenetic factor in HIV-induced immunodeficiency, the role of circulating immune complexes as a possible cause for this shift should be considered.

[Immune complexes induce the secretion of Th2 cytokines in human monocytes]

Two experimental models of immune complexes were used to study the secretion of interleukin (IL)-10, IL-6, IL-1 beta and TNF-alpha by human monocytes in vitro. Immune complexes formed of tetanus toxoid and polyclonal anti-tetanus toxoid antiserum as well as heat-aggregated human serum immunoglobulins induced the release of IL-6 and IL-10 in a dose- and antigen: antibody ratio-dependent manner. Antigen-antibody complexes formed near equivalence were most effective in induction of a cytokine response. Additionally, we demonstrated that endogenously synthesized IL-10 limited the immune complex-induced secretion of proinflammatory cytokines tumor necrosis factor-alpha, IL-6 and IL-1 beta. IL-10 is an anti-inflammatory cytokine and closely associated with the T helper type 2 (Th2) immune response. We conclude that immune complexes, besides their well known ability to cause acute and chronic inflammation, can mediate immunosuppressive effects and influence the balance of Th1/ Th2 responses.

[Nutrition and mortality from some diet-related diseases]

Authors analysed changes in consumption of selected food groups (cereals, fruit, vegetables, meat, fat, sweets) as well as mortality indexes (CVD, intestinal cancers, diabetes) among four European countries (the Netherlands, United Kingdom, Norway, Sweden) during 1970-1992. It was shown that consumption of fruit and vegetables (except the Netherlands) significantly increased. The growing tendency of meat consumption was decelerated, whereas no changes were observed in case of cereals, total fats and sweets. However (except Sweden) fats of animal origin decreased in favour of vegetable ones. As far as mortality from CVD and stomach cancer is concerned some decrease was observed in all countries. In addition mortality from intestine and colon cancer was lower in Sweden as well as UK. Although changes in dietary pattern are playing the crucial role observed mortality rates, other factors related to style of life incl. smoking or physical activity should not be overlooked.

Does an additional source of pulmonary blood flow alter outcome after a bidirectional cavopulmonary shunt?

BACKGROUND

The bidirectional cavopulmonary shunt has become an important intermediate step in the treatment of pediatric patients with single ventricle physiology who are ultimately destined for palliative surgery. We wanted to know whether there would be risks or benefits if an additional source of pulmonary blood flow was left after a bidirectional cavopulmonary shunt.

METHODS AND RESULTS

We retrospectively reviewed the medical and surgical records of all patients who underwent a bidirectional cavopulmonary shunt at the Children's Hospital of Wisconsin between January 1991 and December 1993. A total of 43 patients were identified. Anatomic diagnoses included double inlet left ventricle (14 patients), tricuspid atresia (8 patients), pulmonary atresia with intact septum (6 patients), single right ventricle (5 patients), hypoplastic left heart (3 patients), unbalanced atrioventricular septal defect (3 patients), and other complex lesions (4 patients). We then divided the patients into two groups for purposes of analysis. Group 1 had only the cavopulmonary shunt as a source of pulmonary flow (22 patients); group 2 had an additional source of pulmonary flow (21 patients). Patient age at the time of cavopulmonary shunt ranged from 6 months to 12 years, with group 1 patients being younger (31 versus 45 months, P = .05). Group 2 patients had higher postoperative central venous pressures (17.8 versus 14.1 mm Hg, P < .001) and oxygen saturations (86% versus 81%, P < .001) than did group 1 patients. There was no statistical difference between groups in the number of chest tube days or hospital days. There was 1 early death in group 1 related to severe ventricular dysfunction and 1 late death in group 2 related to sepsis. Five patients in group 2 were readmitted to the hospital for drainage of a large chylothorax compared with none in group 1 (P < .02).

CONCLUSIONS

We conclude that patients with an additional source of pulmonary blood flow after bidirectional cavopulmonary shunt have higher postoperative central venous pressures, have higher oxygen saturations, and are at risk for the late development of a chylothorax.

S15261 antagonises amylin-induced impaired glucose tolerance

Amylin has been postulated to antagonise or inhibit the action of insulin in peripheral rat tissues and thus contribute to, or be responsible for, the development of insulin resistance. We have recently reported that S15261 is a compound capable of increasing insulin sensitivity in ageing insulin resistant rats. In order to assess whether S15261 had any effects on amylin induced insulin resistance we used a model where amylin causes an impairement in glucose tolerance in an acute manner, by means of an intraportal infusion of the hormone in normal rats. We report here that S15261 can antagonise this amylin-induced impaired glucose tolerance.

Reduction of post-traumatic intracranial hypertension by hypertonic/hyperoncotic saline/dextran and hypertonic mannitol

Cerebral injury is seen in one of three patients with multiple traumas; thus efficient shock treatment is a most important measure against the development of secondary brain damage. Small-volume resuscitation in severe hemorrhagic shock by hypertonic/hyperoncotic saline/dextran has been shown to instantaneously normalize cardiac output and to raise systemic blood pressure. In this study, the fluid regimen was compared with hypertonic mannitol to investigate their therapeutic efficacy in intracranial hypertension. The experiments were performed in rabbits subjected to a focal lesion of the brain to induce acute, vasogenic brain edema. The resulting intracranial hypertension was enhanced in a standard manner by inflation of an epidural balloon until an intracranial pressure (ICP) of 17 mm Hg was obtained. Intravenous administration of either 7.2% saline/10% dextran-60 or of 20% mannitol rapidly decreased the elevated ICP. After the first injection, ICP lowering was maintained longer by the mannitol than by the hypertonic saline/dextran, whereas no differences in duration of ICP lowering were found when the infusions of these solutions were repeated. The systemic blood pressure increased after injection of the saline/dextran solution, but it tended to decrease after injection of the mannitol. Transient increases in plasma osmolality, colloid-osmotic pressure, and plasma-Na+ were more pronounced after administration of the saline/dextran solution than after the administration of the mannitol. No difference in the tissue water content between the traumatized and contralateral hemisphere was observed in the animals receiving mannitol; however, after saline/dextran infusion, the water content was somewhat increased in the exposed hemisphere but decreased in the nonexposed, contralateral hemisphere (decreased to a point even below the corresponding level of animals who received the mannitol). The increase of the cerebral water content of the traumatized hemisphere was associated with a respective increase of the cerebral Na+ content and a (nonsignificant) decrease of the K+ content. The present findings demonstrate that the hypertonic/hyperoncotic saline/dextran was as efficient as the mannitol in reducing ICP that had been increased by a cerebral lesion and a space-occupying mass; the underlying mechanisms responsible for the reduction might differ. Because of the powerful hemodynamic properties of the saline/dextran in circulatory shock, administration of the solution in patients with multiple traumas and head injury might be particularly advantageous for the prevention of secondary ischemic brain damage.

Endo-N-acetyl-beta-D-glucosaminidase and peptide-N4-(N-acetyl-glucosaminyl) asparagine amidase activities during germination of Raphanus sativus

Endo-N-acetyl-beta-D-glucosaminidase (ENGase, EC 3.2.1.96) and peptide-N4-(N-acetyl-beta-D-glucosaminyl) asparagine amidase (PNGase, EC 3.5.1.52) activities were monitored during germination and postgerminative development in Raphanus sativus. The PNGase activity was found in dry seeds and its level was constant during germination and postgermination. The ENGase activity was first detected about 18 hr after the start of imbibition (HAI) and displayed a maximum level at 36 HAI. After 36 HAI the production of both enzymes was constant until days 4-5. Both enzymes displayed substrate specificities corresponding to the potential glycoprotein substrates found in plants. They are in agreement (i) with the hypothesis that ENGase and PNGase are at the origin of the production of 'unconjugated N-glycans' and (ii) with the possibility that protein activity could be regulated by the removal of N-glycans.