CRDS with a VECSEL for broad-band high sensitivity spectroscopy in the 2.3 µm window.

The integration of an industry ready packaged Sb-based Vertical-External-Cavity Surface-Emitting-Laser (VECSEL) into a Cavity Ring Down Spectrometer (CRDS) is presented. The instrument operates in the important 2.3 µm atmospheric transparency window and provides a high sensitivity (minimum detectable absorption of 9 × 10(-11) cm(-1)) over a wide spectra range. The VECSEL performances combine a large continuous tunability over 120 cm(-1) around 4300 cm(-1) together with a powerful (∼5 mW) TEM00 diffraction limited beam and linewidth at MHz level (for 1 ms of integration time). The achieved performances are illustrated by high sensitivity recordings of the very weak absorption spectrum of water vapor in the region. The developed method gives potential access to the 2-2.7 µm range for CRDS.

Radioimmunodetection of medullary thyroid carcinoma using indium-111 bivalent hapten and anti-CEA x anti-DTPA-indium bispecific antibody.

UNLABELLED: Pretargeting labeled bivalent hapten with bispecific antibodies has proven feasible in the clinic, and our earlier results have suggested the technique may be very sensitive for detecting small recurrences and metastases. Medullary thyroid carcinoma (MTC) is an example where this technique may be the most useful since local recurrences and isolated metastases are removed surgically when detected, and thyrocalcitonin provides a specific and sensitive tumor marker. In our current study, we evaluated pretargeted immunoscintigraphy in a larger number of MTC patients. METHODS: Anti-carcinoembryonic antigen (CEA) x anti-diethylenetriaminepentaacetic acid (DTPA) indium bispecific antibody and 111In-labeled bivalent DTPA hapten were administered sequentially (4-5 days apart) to 44 patients with elevated circulating calcitonin after resection of primary MTC. Immunoscintigraphy was performed 2, 5 and 24 hr after hapten injection and, when necessary, at longer time intervals. When available, a handheld gamma probe was used during surgery. RESULTS: Fifteen patients had known tumor sites before immunoscintigraphy. Tumors were imaged in 12 (80%) of these patients, including 3 with liver metastases. Five unknown tumor sites were detected. For the 29 patients with occult disease, immunoscintigraphy detected high-activity uptake sites in 21 patients (72%), including 5 in the liver. Twelve were confirmed by surgery, 1 by guided morphologic imaging and 1 by venous catheterization. There were 2 false-positive patients. The other 5 patients have not yet been confirmed. All detected liver metastases were high-activity uptake areas. Radioimmunoguided surgery was used in 14 patients. It was considered helpful by the surgeon in 12 patients, including 4 patients where it determined the resection of small, not palpable nor visible, tumor-involved lymph nodes. Surgical resection resulted in a significant decrease (8 patients) or normalization (1 patient) of circulating calcitonin and CEA. CONCLUSION: This technique affords high sensitivity and specificity for detecting small tumor lesions including liver metastases. Its use for immunoscintigraphy and guided surgery should improve the therapeutic management of recurrent MTC.

Action of metformin on erythrocyte membrane fluidity in vitro and in vivo.

The lipid domains of the cell membrane are believed to be one of the sites where biguanides exert their antihyperglycemic effect. We have examined the effects of metformin on the membrane fluidity of intact erythrocytes in vivo and in vitro. Membrane fluidity was measured by monitoring changes in the anisotropy of the fluorescent probe 6-antroyloxystearic acid (6-AS). The erythrocyte membranes from patients with non-insulin dependent diabetes mellitus treated with metformin were more fluid than those from non-insulin dependent diabetes mellitus patients treated by diet or healthy controls. There was no correlation between membrane fluidity and the plasma lipids or the parameters of metabolic control, suggesting that the high fluidity is an effect of metformin itself. Incubation of erythrocytes from healthy controls and diabetic patients treated by diet or glibenclamide with metformin in vitro confirmed that metformin increases the fluidity of erythrocyte membranes. In vitro metformin did not alter the fluidity of membranes from diabetic patients treated with metformin, perhaps because the basal high fluidity due to their in vivo interaction with plasma metformin could be increased no further. Since insulin appears to be required for the antihyperglycemic effect of metformin, the effect of insulin on membrane fluidity was also evaluated. Insulin generally had a small fluidizing effect on erythrocytes in vitro. The fluidizing action of both insulin and metformin could represent a membrane event common to the hormone and drug leading to additive or synergistic effects in vivo.

[Severe hyponatremia disclosing adenohypophyseal insufficiency with empty sella syndrome]. / Hyponatrémie sévère révélatrice d'une insuffisance anté-hypophysaire avec selle turcique vide.

We report a case of extremely severe hyponatraemia which led to the discovery of anterior hypophysis insufficiency associated with empty sella turcica in a dysimmune context. This type of hyponatraemia is consecutive to corticotropic and thyreo-tropic hormones deficiency and to inappropriate secretion of arginine vasopressin. These endocrine abnormalities are of suprapituitary origin. They can be explained by a hypothalamo-hypophyseal dysregulation of little known mechanism, or by a lesion of the hypothalamus.

[Value of ketoconazole in the treatment of Cushing disease]. / Intérêt du kétoconazole dans le traitement de la maladie de Cushing.

Ketoconazole has been successfully used in short-term treatment of Cushing's syndrome. We treated 4 patients who had Cushing's disease with ketoconazole administered during 5 to 18 months. Two of them are still controlled after 15 months of treatment and 7 months after treatment was withdrawn. In the other two patients, treatment was ineffective primarily and after 5 months. Our data confirm the usefulness of ketoconazole in the treatment of Cushing's disease, but they also show that primary resistance and tachyphylaxis in long-term treatment may occur, as previously reported.