Self-representation in Kleine-Levin syndrome: a single case fMRI study.

Kleine-Levin syndrome (KLS) is characterized by recurrent episodes of hypersomnia, compulsive hyperphagia, disinhibition, hypersexuality and self modifications. To investigate the Self, we used afunctional magnetic resonance imaging paradigm evaluating Self-reference processing (SRP) and Self-reference effect (SRE) in a17-year-old male adolescent at the end of an episode. We observed enhanced activations in right hemisphere and posterior areas- associated with physical Self representations- during the SRP condition, while during the SRE condition, enhanced activations in bilateral but prevailing left frontal areas- associated with the conceptual Self. These results suggest amodified Self during aKLS episode being more physically grounded.

Radioimmunoassay of cortisone in serum, urine, and saliva to assess the status of the cortisol-cortisone shuttle.

We have developed a new assay for cortisone (E) in serum, saliva, and urine involving Celite chromatography followed by RIA with 125I-labeled E and scintillation proximity assay. The chromatography step separates cortisol (F) from E, and in combination with their RIAs, permits assessment of the status of the F-E shuttle. We report the results of basal, postcorticotropin (ACTH), and postdexamethasone E and F concentrations and their circadian fluctuations in the serum, saliva, and urine of healthy volunteers. The serum and urine F/E ratios were increased in patients with ectopic ACTH secretion, whereas in adrenal adenoma and Cushing disease only the urinary ratio was increased. In chronic renal insufficiency this ratio was increased in serum (23.5 +/- 3.9) but diminished in saliva (0.38 +/- 0.11), and in apparent mineralocorticoid excess the ratios were high in serum (44.3 +/- 9.3) and urine (5.35 +/- 0.85) compared with those of healthy subjects (serum 9.8 +/- 3.5, urine 0.52 +/- 0.29, saliva 0.52 +/- 0.29).

Photoaffinity labeling of the human red-blood-cell urea-transporter polypeptide components. Possible homology with the Kidd blood group antigen.

The tritiated urea analogue 1-(3-azido-4-chlorophenyl)-3methyl-2-thiourea ([3H]MeACPTU) was used as a probe to photolabel the human red-blood-cell membrane facilitated urea transporter. On irradiation, [3H]MeACPTU incorporated irreversibly into white ghost membranes. SDS/gel electrophoresis of membranes revealed radioactive incorporation in five major bands of 200, 110, 60, 40 and 14 kDa. The labeling of the 40-kDa and 60-kDa bands was partly prevented by the presence of a high concentration of other urea analogues such as thiourea and 1-(3,4-dichlorophenyl) 2-thiourea (DCPTU). The photolabeling pattern obtained with white ghosts of the Kidd blood-group type Jk(a-,b-) showed no labeling of the 40-kDa polypeptide. Protecting experiments carried out with anti-Jka, anti-Jkb and anti-Jk3 sera prevented radioactive incorporation in the 60-kDa band and in the 110-kDa band. Urea permeability of pink ghosts of blood type Jk(a+,b+) measured in the presence of Jk3 antibodies was 19% lower than the control values. However, urea permeability of frog urinary bladder epithelial cells was not affected by the presence of Jk-reactive antibodies. These results support the hypothesis that the Kidd antigen and the facilitated urea transporter are the same protein. Our estimation of the number of copies in each cell is close to that of the previously published value of 14000.

Urea derivatives as tools for studying the urea-facilitated transport system.

The effects of urea structural analogues on the urea-facilitated diffusion system were examined in human red cell membranes (pink ghosts) and in antidiuretic hormone(ADH)-stimulated frog urinary bladder epithelia. In both tissues, urea permeability (P(urea)) was dramatically but reversibly inhibited by a number of urea analogues, such as 1-(3,4-dichlorophenyl)-2-thiourea (DCPTU). This urea derivative reduced the urea flux in a dose-dependent manner (90% inhibition of P(urea) at 0.5 mM concentration of DCPTU). With the aim of obtaining irreversible markers of red cell and urinary bladder urea transport systems, urea derivatives were modified by addition of an azido residue (N3) and preliminary experiments of photoaffinity labelling were carried out. Two synthetic urea derivatives: 1-(3-azido-4-chlorophenyl)-2-thiourea (ACPTU) and 1-(3-azido-4-chlorophenyl)-3-methyl-2-thiourea (Me-ACPTU) were shown to be very potent inhibitors of P(urea) when used in the absence of light, with IC50 values 60.3 microM and 31.6 microM respectively, as measured in frog urinary bladder. Both these molecules appeared to bind covalently to the urea carrier in both frog urinary bladder and human pink red cell ghosts, when illuminated in the presence of the tissue: the urea flux, which fell to 30-70% of the value obtained in the presence of ADH after inhibitor addition, remained low after the preparation had been illuminated for 30 min and the inhibitor removed. These results provide an interesting approach to the urea carrier analysis, particularly to the urea or urea analogue binding site on the transport protein.