Behavioral profiles of genetically selected aggressive and nonaggressive male wild house mice in two anxiety tests

Artificially selected aggressive (SAL) and non-aggressive (LAL) male house mice were tested in a hexagonal tunnel maze and light-dark preference (LD) box to determine if the bidirectional selection for aggressive behavior leads to a coselection for different levels of trait anxiety. The tunnel maze consists of an open, brightly lit central arena surrounded by a complex system of interconnecting tunnels. As in the LD box, animals which spend less time and are less active in the brightly illuminated section of the maze are considered to have higher anxiety levels. In the tunnel maze, the LAL mice showed more exploration and spent more time in the central arena than the SAL animals, but only during the final 2 min of the 6-min test. This reduced preference for the central arena was not due to general inactivity or a failure of the SAL to find the central arena and indicates a higher level of state anxiety in the aggressive animals. In contrast, no "anxiety-like" differences were found in the LD box, either for the percentage of time spent in the light compartment or for the number of crossings. SAL males actually showed higher levels of moving and rearing, and lower levels of freezing, than did LAL males.

Calcium-induced conformational change in fragment 1-86 of factor X

Time-resolved fluorescence of the single tryptophan residue Trp41 in fragment 1-86 of factor X (FX F1-86) is studied using a time-correlated single photon counting technique with synchrotron radiation as the excitation source. Calcium ions are believed to induce a conformational change in the N-termini of the activated factor X and other vitamin K dependent proteins, which is accompanied by a decrease in fluorescence intensity. The titration with calcium yields a sigmoidal fluorescence titration curve with a transition midpoint concentration of 0.44 mM. The wavelength-dependent tryptophan fluorescence decays of the apo-FX F1-86 (in the absence of calcium) and Ca-FX F1-86 are characterized by conventional multiexponential analysis and fluorescence lifetime distribution analysis. In the absence of calcium there are three significant classes of fluorescence lifetimes (ns) that are nearly wavelength independent: 0.55 +/- 0.08 (component A), 2.6 +/- 0.1 (component B), and 5.3 +/- 0.3 (component C). However, their preexponential amplitudes vary with wavelength. The decay associated emission spectra of the individual components show that components B and C contribute over 85% to the total fluorescence for all examined wavelengths. However, in the presence of calcium, the analysis of the time-resolved fluorescence data of Ca-FX F1-86 yields four wavelength-independent lifetimes (ns) of 0.30 +/- 0.09 (component D), 0.65 +/- 0.10 (component A), 2.7 +/- 0.2 (component B), and 5.4 +/- 0.3 (component C). Calcium addition to the apo-FX F1-86 leads to a decrease in the fluorescence intensities of components B and C while their decay times remain unaffected. In Ca-FX F1-86 an additional component D arises that has a decay time of 0.30 ns and that contributes up to 35% to the total fluorescence intensity. A comparison with a previous investigation of prothrombin fragment 1 demonstrates the extensive structural and functional homology between the N termini of prothrombin and factor X(a).

Dual epitope recognition by the VASP EVH1 domain modulates polyproline ligand specificity and binding affinity

The Ena-VASP family of proteins act as molecular adaptors linking the cytoskeletal system to signal transduction pathways. Their N-terminal EVH1 domains use groups of exposed aromatic residues to specifically recognize 'FPPPP' motifs found in the mammalian zyxin and vinculin proteins, and ActA protein of the intracellular bacterium Listeria monocytogenes. Here, evidence is provided that the affinities of these EVH1-peptide interactions are strongly dependent on the recognition of residues flanking the core FPPPP motifs. Determination of the VASP EVH1 domain solution structure, together with peptide library screening, measurement of individual K(d)s by fluorescence titration, and NMR chemical shift mapping, revealed a second affinity-determining epitope present in all four ActA EVH1-binding motifs. The epitope was shown to interact with a complementary hydrophobic site on the EVH1 surface and to increase strongly the affinity of ActA for EVH1 domains. We propose that this epitope, which is absent in the sequences of the native EVH1-interaction partners zyxin and vinculin, may provide the pathogen with an advantage when competing for the recruitment of the host VASP and Mena proteins in the infected cell.

First Mass-resolved Measurement of High-Energy Cosmic-Ray Antiprotons

We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28-29 from Fort Sumner, New Mexico. The measured p&d1;/p ratio is in agreement with a pure secondary interstellar production.

Differential susceptibility to periodontitis in genetically selected Wistar rat lines that differ in their behavioral and endocrinological response to stressors

This study tests the model presented previously by Breivik et al. (1996), in which the extent of periodontitis, an inflammatory disease, is predicted from the reactivity of the HPA-axis. Briefly, the model implies that elevated plasma levels of corticosterone modulate the immune system by shifting the T-helper balance toward a more Th2 response, which, alternately, increases the sensitivity to periodontitis. To test this model, two genetically distinct types of rats that differ both behaviorally and endocrinologically in their response to stress (high corticosterone responding APO-SUS rats and low corticosterone responding APO-UNSUS rats) were compared. Periodontitis was experimentally induced through the placement of a ligature and measured as the extent of tissue (fiber and bone) loss, both histologically and radiographically. The results show that, as expected, APO-SUS animals are more sensitive to periodontitis, i.e., show more fiber and bone loss, than APO-UNSUS animals. These data are in agreement with findings in Fischer and Lewis rats, as well as with corticosterone treated and adrenalectomized animals and suggest that genetic factors underlying the variation in the reactivity of the HPA-axis (and, accordingly, their behavioral response to stress) play an important a role in the development of inflammatory diseases.

Binding of prothrombin and its fragment 1 to phospholipid membranes studied by the solvent relaxation technique

The phospholipid headgroup mobility of small unilamellar vesicles composed of different mixtures of phosphatidyl-L-serine (PS) and phosphatidylcholine is characterized by the solvent relaxation behavior of the polarity sensitive dyes 6-propionyl-2-(dimethylamino)naphthalene (Prodan) and 6-palmitoyl-2-[trimethylammoniumethyl]-methylamino]naphthalene chloride (Patman). If the PS content exceeds 10%, the addition of calcium leads to a substantial deceleration of the solvent relaxation of both dyes, indicating the formation of Ca(PS)2 complexes. Addition of prothrombin and its fragment 1 leads to a further decrease of the headgroup mobility, as explained by the binding of more than two PS-molecules by a single protein molecule. Prodan monitors the outermost region of the bilayer and it clearly distinguishes between the binding of prothrombin and its fragment 1. The deeper incalated Patman does not distinguish between both proteins. The validity of the solvent relaxation technique for the investigation of the membrane binding of peripheral proteins is demonstrated by the studies of prothrombin induced changes in the steady-state fluorescence anisotropies of 1,6-diphenyl-1,3, 5-hexatriene.

Picosecond tryptophan fluorescence of membrane-bound prothrombin fragment 1

The wavelength-dependent tryptophan (Trp) fluorescence decays of Ca-prothrombin fragment 1 (Ca-BF1), which contains three tryptophan residues, in the presence of pure phosphatidylcholine (PC) small unilamellar vesicles (SUV) and PC-SUV containing either 25% phosphatidyl-l-serine (PS), and 25% or 40% phosphatidylglycerol (PG) are characterized, using fluorescence lifetime distribution, conventional multiexponential, and global analysis. In analogy to previous investigations on apo- and Ca-BF1 (M. Hof, G.R. Fleming, V. Fidler, Proteins Struct. Func. Genet. 24 (1996) 485-494), the analysis resulted in a five exponential decay model in all investigated systems, where the five fluorescence lifetimes (e.g. 0. 04+/-0.02 ns (component A), 0.24+/-0.02 ns (B), 0.66+/-0.03 ns (C), 2.4+/-0.3 ns (D), and 5.4+/-0.4 ns (E) for Ca-BF1 in the presence of PC-SUV) are wavelength-independent. The fluorescence lifetimes and the corresponding amplitudes of the 'Gla-Trp' (components D and E) and of the two 'kringle-Trp' (components B, C, and D) remain unchanged when bound to the PS-containing vesicles. Saturation binding to PG-containing membranes leads to a prolongation of the Gla component E from 5.3 in solution to 7.5 ns, indicating a change in the Gla-domain conformation. The results represent the first experimental evidence of a lipid-specific conformational change in the N-terminal 'Gla domain' of a vitamin K-dependent protein.

Fluorescence energy transfer on erythrocyte membranes

Stationary and time-dependent fluorescence were measured for a donor/ acceptor (DA) pair bound to membrane proteins of bovine erythrocyte ghosts. The donor N-(p-(2-benzoxazolyl)phenyl)-maleimide (BMI) and the acceptor fluram bind to SH- and NH2-residues, respectively. The fluorescence spectra and the time-dependent emission were consistent with radiationless fluorescence energy transfer (RET). Band3 protein is the only membrane spanning protein with accessible SH-groups for the coupling of BMI molecules, and therefore only acceptor binding sites on the same band3 protein were counted by the RET measurements performed. A density of RET-effective acceptor binding sites c = 0.072 nm-2 was calculated on the basis of the two-dimensional Förster-kinetics.

Solvent relaxation behaviour of n-anthroyloxy fatty acids in PC-vesicles and paraffin oil: a time-resolved emission spectra study

Time-resolved fluorescence measurements were performed for a set of n-anthroyloxy fatty acids (n-AS; n = 2, 3, 6, 9, 12, 16) in both solvent and vesicle systems. The Stokes' shifts and the mean relaxation times calculated from the time-resolved emission spectra (TRES) are shown to be strongly dependent on the position of the fluorophore in small unilamellar vesicles (SUV) composed of phosphatidylcholine (PC), while they are essentially independent of the fluorophore position in isotropic paraffin oil. The concept of an intramolecular relaxation process which had been suggested to explain the wavelength dependence of the emission behaviour of the n-AS dyes in viscous solvents is supported by semiempirical calculations showing that a more planar conformation is favoured in the excited compared to the ground state. However, in order to explain the results in vesicle systems, the concept of intramolecular relaxation is not sufficient. Rather, we show that intermolecular solvent relaxation processes play the dominant role for the wavelength dependent emission behaviour in polar, viscous environments.

Binding and relaxation behaviour of prodan and patman in phospholipid vesicles: a fluorescence and 1H NMR study

The relative location, binding behaviour and the solvent relaxation behaviour of the polarity sensitive membrane probes 6-propionyl-2-(dimethylamino)naphthalene and 6-palmitoyl-2-[[trimethylammoniumethyl]methylamino]naphthalene chloride in vesicles composed of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine or egg yolk lecithin have been compared using steady-state and time-resolved fluorescence as well as high resolution NMR measurements. The reconstructed time-resolved emission spectra show unambiguously that the observed spectral shifts in vesicle systems have to be assigned to time-dependent solvent relaxation processes rather than to a probe relocation mechanism. All fluorescence as well as the NMR relaxation data suggest a deeper localization of Patman in the membrane, sensing a less polar and/or more restricted probe environment.

Prenatal sonographic diagnosis of fetal adrenal gland hemorrhage

BACKGROUND

In newborn the finding of adrenal gland hemorrhage is not uncommon. Only few cases of prenatal diagnosis of fetal adrenal bleeding by sonography have been reported.

CASE

In a 28-year-old nulliparous pregnant woman, routine sonography performed in 35 + 2 weeks of gestational age showed a cystic mass on the upper pole of the right kidney of a male fetus with normal biophysical profile and Doppler flow indices. Sonographic examination demonstrated a spontaneous remission within 3 weeks after uncomplicated vaginal delivery.

CONCLUSION

In the management of adrenal gland hemorrhage of the fetus or newborn, control of remission by sonography is a sufficient tool for differentiation against other tumors and is helpful in preventing unintended surgical removal of the adrenal gland.

Malignant endocrine tumours in childhood and adolescence--results of a retrospective analysis

BACKGROUND

Malignant endocrine tumours (MET) are rare neoplasms in childhood and data on such tumours are scarcely available. The aim of this retrospective study was to collect data over a period of 11 years (1984-1995) and to give the basis for a prospective study.

PATIENTS AND METHOD

180 departments of paediatrics, nuclear medicine and children's surgery were asked for reporting of patients with MET by a questionnaire. 35% of the departments answered (however, 75% of the paediatric departments).

RESULTS

96 children with MET were reported: 73 with thyroid cancer (50 papillary, 15 follicular, 7 medullar, 1 anaplastic; 1:1,9 boys to girls, both mean and median age 11 3/4 years), 12 with adrenocortical cancer and 11 with other malignant endocrine tumours. Metastases were found at diagnosis in 41 of 65 children with papillary or follicular carcinoma. 37 patients (pts.) are in first continuous complete remission (CCR), 4 in partial remission (PR) and in 24 (!) children the remission state or the outcome is not known. 6 of 7 children with medullary cancer have had metastases at diagnosis. 1 patient is in CCR, 1 patient is living in PR, 1 in relapse. 4 children are lost of follow up (lfu.). In sex-ratio no difference was found in 12 pts. suffering from adrenocortical cancer (mean age 5 1/4 years, median age 2 1/2 years). 11 tumours showed hormonal activity. 5 children disclosed metastases at diagnosis. All patients were treated by surgery, 6 received chemotherapy additionally. 4 children are living in CCR, 3 pts. in remission of unknown state, 4 died (all of them with metastases at diagnosis), 1 patient is lfu. The other MET reported: 8 carcinoids (7 x appendix, 1 x lung), 2 phaeochromocytomas, 1 islet cell cancer. 8 pts. are in CCR, 2 are lfu. The child with the islet cell carcinoma died.

CONCLUSIONS

Since only 35% of the clinics answered this retrospective analysis cannot give any statement about the incidence of MET in children. As to the prognosis thyroid cancer seems to have a favourable prognosis in childhood and adolescence. In contrast, metastatic adrenocortical cancer is incurable in this age group. Carcinoids of the appendix can be treated curatively by appendectomy. To better understand the biology of MET in children and adolescence and to achieve a better prognosis for some types of these tumours, much more data are needed. For these reason a multicenter prospective therapy study for childhood MET seems to be necessary.

Time-resolved fluorescence study of a calcium-induced conformational change in prothrombin fragment 1

The wavelength dependent fluorescence decay properties of bovine prothrombin fragment 1 have been investigated employing a picosecond time-correlated single photon counting technique. All observations are discussed with using the crystal structure (Soriano-Garcia et al., Biochemistry 31:2554-2566, 1992). Fluorescence lifetimes distribution and conventional multiexponential analysis, as well as acrylamide quenching studies lead to the identification of six distinguishable tryptophan excited-states. Accessibility to the quencher and the known structure are used to associate a fluorescence decay of the tryptophan present in the Gla domain (Trp42) with two red shifted components (2.3 and 4.9 ns). The two kringle domain tryptophans (Trp90 and Trp126) exhibit four decay times (0.06, 0.24, 0.68, and 2.3 ns), which are blue shifted. The calcium-induced fluorescence quenching is a result of static quenching: the five decay times remain unchanged, whereas the fluorescence intensity of Trp42 is decreased. The static quenching process is a consequence of a ground state interaction between the Cys18-Cys23 disulfide bridge and Trp42. The monomolecular equilibrium constant for this disulfide-pi-electron interaction is found as 4.8.

Influence of vesicle curvature on fluorescence relaxation kinetics of fluorophores

The effect of membrane curvature on the fluorescence decay of 2-p-toluidinyl-naphthalene-6-sulfonic acid (TNS), 2-(9-anthroyloxy) stearic acid (2-AS) and 12-(9-anthroyloxy)-stearic acid (12-AS) was investigated for egg lecithin vesicles of average diameter dm = 22 nm and 250 nm. The biexponential fluorescence decay of TNS at the red edge of the emission spectrum was analysed according to the model of Gonzalo and Montoro [1]. Over the entire temperature range (1-40 degrees C) the small TNS labelled vesicles showed significantly shorter solvent relaxation times tau(r) than their larger counterparts (e.g. 1.3 ns compared with 2.1 ns at 5 degrees C), indicating a higher mobility of the hydrated headgroups in the highly curved, small vesicles. The fluorescence decay of both AS derivatives is also biexponential. While the shorter decay times (1-3 ns) are practically identical for small and large vesicles, the longer decay times (5-14 ns) are identical only for 12-AS but not for 2-AS. This indicates that the microenvironment is similar in small and large vesicles deep in the membrane in spite of the differences in curvature.

Comparison of the membrane binding kinetics of bovine prothrombin and its fragment 1

Total internal reflection fluorescence microscopy has been used to compare the membrane binding characteristics of fluorescein-labeled bovine prothrombin and fluorescein-labeled bovine prothrombin fragment 1. The Ca(2+)-dependent association of these proteins with quartz-supported planar membranes composed of mixtures of phosphatidylserine (2-10 mol%) and phosphatidylcholine was examined. Equilibrium binding measurements showed that the apparent equilibrium dissociation constants increased with decreasing molar fractions of phosphatidylserine and that the dissociation constants were somewhat lower for intact prothrombin. Kinetic measurements, using fluorescence photobleaching recovery, showed that the measured dissociation rates were approximately equivalent for prothrombin and fragment 1 and did not change with the protein solution concentration or the molar fraction of phosphatidylserine. The kinetic data also implied that the surface binding mechanism for both proteins is more complex than a simple reversible reaction between monovalent proteins and monovalent surface sites. Measured equilibrium and kinetic constants are reported and compared for prothrombin and fragment 1 on planar membranes.

Roberts syndrome and SC phocomelia. A single genetic entity

A family with three siblings showing different manifestations of Roberts syndrome or SC phocomelia is described. With regard to previously published cases of familial Roberts syndrome and SC phocomelia we conclude that these two syndromes are one and the same genetic entity.