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The electronic state of Mn atoms in mixed valence manganites has been studied by means of X-ray absorption spectroscopy at the Mn K-edge. Higher resolution than in conventional measurements has been achieved by measuring the Mn Kbeta fluorescence line. We have found a unique resonance at the edge in the XANES spectra of intermediate composition RE1-xCa(x)MnO3 samples. The features of these XANES spectra do not depend on small changes in the local structure around the Mn atom. However, the spectra of the intermediate composition samples can not be reproduced by a linear combination of REMnO3 and CaMnO3 spectra. Accordingly, the electronic state of Mn atoms in these compounds can not be considered as a mixture of Mn3+ and Mn4+ pure states.

The structure of the high-affinity cation-binding site of bacteriorhodopsin was studied using extended x-ray absorption fine structure techniques. The results obtained for Mn2+ in aqueous solution and for the complex BR-Mn2+ (1:1 molar ratio) show great similarities, suggesting that Mn2+, when bound to this site, is coordinated with six atoms of oxygen, forming an octahedral disposition. The interatomic distance between the atoms of oxygen and the Mn2+ was found to be 2.17 A for the complex BR-Mn2+, similar to Mn2+ in solution (2.15 A). In addition, the absence of any other peak at greater distances in the Fourier-transformed spectrum indicates that neither phosphorus nor sulphur atoms are present in the second coordination shell. This suggests that this binding site is located in the protein, discarding the proximity of lipid polar headgroups.

A case of primary hyperparathyroidism with prevalent neuromuscular symptoms is described. Clinical, diagnostic and therapeutic implications are emphasized. Particular attention must involve a full clinical examination, electromyographic data and neuromuscular biopsy to make differentiation from primary myopathy or denervation pathology. Some similarity of electromyographic data with those observed in botulism and myastenia gravis should also be taken in mind. Hypercalcemia could play a pathological role in conditioning abnormalities of nervous impulse conduction at the level of neuromuscular junction. Another possible interference might be related to a direct effect of parathormone and hypophosphataemia on nervous impulse conduction. "Glandular hyperplasia", as observed in this case at istologic examination, rises some problems as far as the prognosis is concerned.

Ten hairy-cell leukemia patients were treated with interferon beta (IFN-beta) at a dose rate of 2 x 10(6) IU/m2 x 5 days for 4 weeks (induction therapy) and, thereafter, at the same dose three times a week for 11 months (maintenance therapy). The effect of this treatment on serum neopterin, beta 2-microglobulin, (2'-5')oligoadenylate [(2'-5')An] levels, intracellular (2'-5')An values and human Mx protein synthesis was analysed. There were significant rises in serum neopterin and (2'-5')An levels during both induction and maintenance, whereas beta 2-microglobulin levels rose only during induction. Rises in intracellular (2'-5')An were documented mainly during induction, but they were not significantly higher than pretherapy values. IFN beta provoked an increase in human Mx protein synthesis over the entire induction-maintenance period, but was only significantly higher than baseline during induction. All markers proved useful for monitoring the effects of IFN beta dose schedules, but were not predictive of clinical outcome. Natural killer activity and IFN gamma production, which were initially defective, followed a different trend from that of the other factors studied, in that increases were documented only late in the course of therapy when the disease was already in remission.

To assess influence of host response to interferon-beta (IFN-beta), on biochemical parameters, beta 2-microglobulin (beta 2-M) and neopterin were evaluated in 15 and 12 patients respectively before and 24 h after 1-46 X 10(6) IU intravenously (i.v.) IFN-beta given every other day. In 4 additional patients, both molecules were determined before and after 24, 48, 72, and 96 h of weekly IFN-beta injections. Serum beta2-M levels significantly increased 24 h after IFN-beta administration in the overall group of 15 patients treated with the alternate day schedule (p = 0.003) as well as in the group of patients treated with the weekly schedule (p = 0.00003). Maximum induction of beta 2-M was observed 24 h after a single weekly IFN-beta injection, but the levels of this protein 72 h after still remained significantly higher than baseline values (p = 0.001). This demonstrates the progressive accumulation of beta 2-M in the circulation produced by the continuous IFN administration. Nevertheless, in patients treated with both IFN treatment schedules, a clear correlation between the increments of beta 2-M and the IFN-beta doses was observed (p = 0.00002 and p = 0.0016 for the alternate day and the weekly schedule respectively). Furthermore the under curve area (AUC) of 48 h beta 2-M levels after IFN administration significantly rose (p less than 0.05) with increasing IFN doses in 4/6 patients. In spite of the accumulation of beta 2-M in the circulation, the overall serum values of this protein 24 h after each successive IFN-injection, in the 15 patients receiving the alternate-day treatment, were significantly higher than before the immediate preceding dose both in patients with initially normal and those with initially high base levels (p = 0.00055 and p = 0.011, respectively). As with beta 2-M, neopterin levels significantly rose during IFN treatment (p less than 0.05) in the group of patients as a whole. After single weekly IFN-beta injections, maximum induction of neopterin was observed 24 h after administration, then the levels of this molecule slowly declined towards the baseline levels, but 96 h after, its levels were still significantly elevated (p less than 0.00001). Neopterin induction was not related to IFN-beta doses, but the levels of this molecule both before and after IFN administration were correlated with an increase in the number of IFN injections (p = 0.0006 and p = 0.0009, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

In 25 heroin addicts examined an initial alteration in microcirculatory homeostasis was found ond held to be responsible for the addiction. As in other cases it is thought possible to use the chronobiological course of haemodynamic balance and imbalance as a biological marker for prevention and treatment.

The antihypertensive effect of ketanserin, a recent 5-hydroxytryptamine (5-HT) antagonist, which acts on the 5-HT2-subtype receptor, was evaluated in 10 patients of both sexes (age range 35-69 years) with mild to moderate essential hypertension. Blood pressure and heart rate were measured at rest, in supine and standing position at the end of two weeks of placebo washout and after 2, 4 and 8 weeks of treatment with ketanserin 20 mg twice daily as monotherapy, while the changes of blood pressure and heart rate during static (hand-grip) and dynamic (bicycle ergometer) exercise were evaluated at the end of placebo and of the fourth week of therapy. The treatment induced a highly significant reduction of supine and standing systolic and diastolic blood pressure during rest, without any significant change in heart rate. During dynamic exercise, the increase in systolic and diastolic blood pressure and heart rate was not blunted by ketanserin, while the drug reduced systolic blood pressure and heart rate increase, during static exercise, with no change of diastolic blood pressure. From these data it may be concluded that ketanserin lowers blood pressure in essential hypertension without any interference with cardiovascular reflexes related to standing or dynamic exercise, and reduces the increase of systolic blood pressure and heart rate during static exercise with favourable interference on myocardial oxygen consumption. This sparing effect on myocardial oxygen demand is particularly relevant in hypertensive patients with asymptomatic coronary disease engaged in normal daily physical activity which includes many forms of static exercise.

Twenty-two patients with advanced malignancies were treated with low-dose cytosine arabinoside (ara-C) (45 mg/m2 sc every 12 h for 3 days) and cisplatin (DDP) (100 mg/m2 ev on day 2, 2 h after ara-C. Patients received 61 cycles of ara-C + DDP with a median number per patient of 2.7 cycles (range, 1-5). All patients were evaluable for toxicity and response. Overall, 6 of 22 patients (27%) obtained an objective response (2 CR + 4 PR) with a median response duration of 20 weeks. Hematologic and gastrointestinal toxicities were moderate. Our results show a low response rate with the ara-C and DDP combination compared to the interesting results obtained in vitro.