NO rotational orientation following 308 nm photodissociation of NO2

The rotational angular momentum orientation and alignment of the NO fragments generated via linearly polarized 308 nm photodissociation of NO2 has been determined using laser induced fluorescence. By observing the dependence of the photofragment NO Doppler-resolved transition line shapes on experimental geometry, it has proved possible to determine multipole moments of the photofragment angular momentum distribution up to, and including, rank 3. The implications of the results for the mechanism of the dissociation are considered.

Insertion and abstraction pathways in the reaction O(1D2) + H2-->OH+H

Rigorous quantum dynamical calculations have been performed on the ground 1 1A' and first excited 1 1A" electronic states of the title reaction, employing the most accurate potential energy surfaces available. Product rovibrational quantum state populations and rotational angular momentum alignment parameters are reported, and are compared with new experimental, and quasiclassical trajectory calculated results. The quantum calculations agree quantitatively with experiment, and reveal unequivocally that the 1 1A" excited state participates in the reaction.

[Serum S100B protein and stage of cutaneous melanoma: a prospective study]

OBJECTIVE

We searched for a correlation between serum S100B protein and cutaneous malignant melanoma stage, according to the American Joint Committee on Cancer staging system, and between elevation of serum S100B protein and development of metastasis.

PATIENTS AND METHODS

We conducted a prospective bicentric study for 20 months in 122 patients with malignant melanoma. LIA-mat(R) assay was used to determine serum S100B at each examination. The optimal cut-off value was determined from the ROC curve.

RESULTS

The optimal cut-off value to discriminate patients with metastases from patients in remission was 0.09 microg/l. Sensitivity was 46 p. 100 in patients with stage III and 86 p. 100 in patients with stage IV disease. The positive predictive value for stage III/IV was 77 p. 100 and the negative predictive value was 89 p. 100. Serial measurements were made in 56 patients. The serum S100B protein level was elevated in 69 p. 100 of the patients disclosing disease progression (9/13). In 44 p. 100 of the patients (4/9), serum S100B protein level rose within a delay of 3 months before new metastases were detected.

DISCUSSION

Our study confirms that serum S100B protein is a tumor marker for melanoma staging and follow-up. A rise in S100B protein precedes or reveals metastasis.

Epithelial sodium channel in human epidermal keratinocytes: expression of its subunits and relation to sodium transport and differentiation

The amiloride-sensitive epithelial sodium channel (ENaC) is a main determinant of sodium absorption in renal and colonic epithelial cells. Surprisingly, it is also expressed in non-transporting epithelia such as the epidermis. To gain insight into the putative role of ENaC in keratinocytes, we have evaluated its expression in human skin and in cultured human keratinocytes. Our results indicate that (1) ENaC is expressed in the epidermis and in cultured keratinocytes, at the mRNA and at the protein levels, (2) the ratio of expression of the different ENaC subunits is drastically modified at the protein level during cell growth and differentiation, with a selective upregulation of the β subunit, (3) no transepithelial sodium transport function is apparent in cultured keratinocytes, but patch-clamp recordings indicate the existence of functional sodium channels with properties similar to those of the cloned ENaC and (4) ENaC inhibition does not alter keratinocyte proliferation, but it significantly decreases the frequency of dome formation in confluent keratinocyte cultures. These results document for the first time the characteristics of ENaC subunit expression in human keratinocytes, and suggest that ENaC may be important during differentiation.