α-Tocopherol Reduces Morphological Changes and Oxidative Stress during Gentamicin-Induced Acute Renal Failure.

We studied the effect of α-tocopherol on gentamicin-induced morphological and functional changes in the kidneys of Wistar rats. Special attention was paid to the ability of α-tocopherol administered in combination with gentamicin to correct ultrastructural changes in the glomerular basal membrane and tubules. Combined treatment with α-tocopherol (100 mg/kg) and gentamicin (100 mg/kg) led to correction of histopathological and biochemical changes and oxidative injury to the kidneys induced by this antibiotic.

Study of small chlorine-doped potassium clusters by thermal ionization mass spectrometry.

The theoretical calculations have predicted that nonmetal-doped potassium clusters can be used in the synthesis of a new class of charge-transfer salts which can be considered as potential building blocks for the assembly of novel nanostructured material. In this work, K(n)Cl (n = 2-6) and K(n)Cl(n-1) (n = 3 and 4) clusters were produced by vaporization of a solid potassium chloride salt in a thermal ionization mass spectrometry. The ionization energies (IEs) were measured, and found to be 3.64 ± 0.20 eV for K(2)Cl, 3.67 ± 0.20 eV for K(3)Cl, 3.62 ± 0.20 eV for K(4)Cl, 3.57 ± 0.20 eV for K(5)Cl, 3.69 ± 0.20 eV for K(6)Cl, 3.71 ± 0.20 eV for K(3)Cl(2) and 3.72 ± 0.20 eV for K(4)Cl(3). The K(n)Cl(+) (n = 3-6) clusters were detected for the first time in a cluster beam generated by the thermal ionization source of modified design. Also, this work is the first to report experimentally obtained values of IEs for K(n)Cl(+) (n = 3-6) and K(n)Cl(n-1) (+) (n = 3 and 4) clusters. The ionization energies for K(n)Cl(+) and K(n)Cl(n-1) (+) clusters are much lower than the 4.34 eV of the potassium atom; hence, these clusters should be classified as 'superalkali' species.

Production and ionization energies of K(n)F (n = 2-6) clusters by thermal ionization mass spectrometry.

RATIONALE: The very small clusters of the type K(n)F are of particular importance since their first ionization energies (IEs) are lower than those of the alkali metal atoms. Theoretical calculation has demonstrated that this kind of cluster represents a potential 'building block' for cluster-assembly materials with unique structural, electronic, optical, magnetic, and thermodynamic properties. To date, however, there have been no experimental results on the IEs of K(n)F (n >2) clusters. METHOD: K(n)F (n = 2-6) clusters were produced by the evaporation of a solid potassium fluoride salt using a modified thermal ionization source of modified design, and mass selected by a magnetic sector mass spectrometer where their IEs were determined. RESULTS: Clusters K(n)F (n = 3-6) were detected for the first time. The order of the ion intensities was K(2)F(+)> > K(4)F(+)> > K(3)F(+)K(6)F(+)> K(5)F(+). The determined IEs were 3.99 ± 0.20 eV for K(2)F, 4.16 ± 0.20 eV for K(3)F, 4.27 ± 0.20 eV for K(4)F, 4.22 ± 0.20 eV for K(5)F, and 4.31 ± 0.20 eV for K(6)F. The IEs of K(n)F increase slightly with the increase in potassium atom number from 2 to 6. We also observed that the presence of a fluorine atom leads to increasing ionization energy of bare metal potassium clusters. CONCLUSIONS: The modified thermal ionization source provides an efficient way of obtaining the fluorine-doped potassium clusters. These results also present experimental proof that K(n)F (n = 2-6) clusters belong to the group of 'superalkali' species.

Formation of positive cluster ions Li(n) Br (n = 2-7) and ionization energies studied by thermal ionization mass spectrometry.

Clusters of the type Li(n)X (X = halides) can be considered as potential building blocks of cluster-assembly materials. In this work, Li(n)Br (n = 2-7) clusters were obtained by a thermal ionization source of modified design and selected by a magnetic sector mass spectrometer. Positive ions of the Li(n)Br (n = 4-7) cluster were detected for the first time. The order of ion intensities was Li(2)Br(+) > Li(4)Br(+) > Li(5)Br(+) > Li(6)Br(+) > Li(3)Br(+). The ionization energies (IEs) were measured and found to be 3.95 ± 0.20 eV for Li(2)Br, 3.92 ± 0.20 eV for Li(3)Br, 3.93 ± 0.20 eV for Li(4)Br, 4.08 ± 0.20 eV for Li(5)Br, 4.14 ± 0.20 eV for Li(6)Br and 4.19 ± 0.20 eV for Li(7)Br. All of these clusters have a much lower ionization potential than that of the lithium atom, so they belong to the superalkali class. The IEs of Li(n)Br (n = 2-4) are slightly lower than those in the corresponding small Li(n) or Li(n)H clusters, whereas the IEs of Li(n)Br are very similar to those of Li(n) or Li(n)H for n = 5 and 6. The thermal ionization source of modified design is an important means for simultaneously obtaining and measuring the IEs of Li(n)Br (n = 2-7) clusters (because their ions are hermodynamically stable with respect to the loss of lithium atoms in the gas phase) and increasingly contributes toward the development of clusters for practical applications.

Formation and ionization energies of small chlorine-doped lithium clusters by thermal ionization mass spectrometry.

RATIONALE: Theoretical calculations have shown that the first ionization energy of clusters of the type Li(n) Cl (n ≥2), with more than eight valent electrons, is lower than that of alkali metal atoms; hence they are named superalkali. Superalkali clusters can mimic the chemical behavior of alkali metals and may be used as building blocks of new cluster-assembled materials. There is currently no reliable experimental proof of this kind of clusters and such proof is required. METHODS: The Li(n) Cl (n = 2-6) clusters were produced by a thermal ionization source of modified design, and mass selected by a magnetic-sector mass spectrometer. The modification pertains to the replacement of the side filaments by a cylinder in the triple-filament thermal ionization source. The sample, which is LiCl salt, was pressed into a ring and placed on the inner wall of the cylinder. RESULTS: It was observed that the ions of clusters with an even number of lithium atoms (Li(2) Cl(+) , Li(4) Cl(+) , Li(6) Cl(+) ) are more stable than the odd-numbered ones (Li(5) Cl(+) , Li(3) Cl(+) ). The ionization energies were determined to be 3.98 ± 0.25 eV for Li(2) Cl, 4.10 ± 0.25 eV for Li(3) Cl, 3.90 ± 0.25 eV for Li(4) Cl, 4.01 ± 0.25 eV for Li(5) Cl, and 4.09 ± 0.25 eV for Li(6) Cl. The presence of a halogen atom reduces the ionization energy of the metal clusters. CONCLUSIONS: The thermal ionization source of modified design presents a suitable simple way to obtaining and measuring the ionization energies of very small lithium monochloride clusters. Clusters Li(n) Cl, n = 4 to 6, were detected for the first time.

Ionization energies of K2X (X=F, Cl, Br, I) clusters.

The electronic structure and properties of dipotassiummonohalides are important for understanding the unique physical and chemical behavior of M(n)X systems. In the present study, K(2) X (here X=F, Cl, Br, I) clusters were generated in the vapor over salts of the corresponding potassium halide, using a magnetic sector thermal ionization mass spectrometer. The ionization energies obtained for K(2)F, K(2)Cl, K(2)Br, and K(2)I molecules were 3.82 ± 0.1 eV, 3.68 ± 0.1 eV, 3.95 ± 0.1 eV, and 3.92 ± 0.1, respectively. These experimental values of ionization energies for K(2) X (X=F, Br, and I) are presented for the first time. The ionization energy of K(2)Cl determined by thermal ionization corresponds to previous results obtained by photoionization mass spectrometry, and it agrees with the theoretical ionization energy calculated by the ab initio method. The presently obtained results support previous theoretical predictions that the excess electron in dipotassiummonohalide clusters is delocalized over two potassium atoms, which is characteristic for F-center clusters.

Aerobic exercise training as a potential source of natural antibodies protective against human immunodeficiency virus-1.

Despite the effectiveness of HAART in controlling HIV-1 replication, the emergence of drug-resistant viruses in infected patients and the severe side effects caused by the currently used drug regimens and the lack of an effective vaccine necessitate the continued search for new therapeutic strategies for prevention and therapy of HIV disease. Previously we reported that natural autoantibodies, recognizing peptide FTDNAKTI (peptide NTM1) derived from the C2 domain of HIV-1 gp120, contribute to the control of HIV disease. Here we demonstrated that sera from well-trained athletic (HIV-negative) subjects showed high reactivity with peptide NTM1. This result confirms that aerobic exercise training stimulates production of natural autoantibodies, which recognize peptide NTM1. Bioinformatics analysis indicates that these natural autoantibodies could slow down disease progression by blocking the superantigenic site on HIV-1 gp120. The results suggest that aerobic exercise training may be a promising non-toxic and inexpensive adjunctive anti-HIV therapy.

The vanadium isotopic constitution of petroleum asphaltenes: La Luna Formation (Venezuela).

High-resolution mass spectrometry indicates that the isotopic abundance of 50V of the Late Cretaceous La Luna petroleum asphaltenes of marine origin (highly enriched with V > 2000 ppm) is higher by about 3.5% than that of the inorganic source (VOSO4 x 5H2O, Merck). We propose that the difference in the 50V/51V values between the La Luna petroleum asphaltenes and the inorganic source can be best ascribed to the biological processing of seawater vanadium. The fact that the V isotopic compositions of petroleum asphaltenes vary over a very narrow range (2.46-2.52) suggests essentially the same (or similar) and fixed biological source of vanadium.

[Epidemiology of Lyme borreliosis]. / Epidemiologija Lyme borreliosis.

Our prospective study covered 1093 patients with epidemiological features and demonstrable clinical manifestations of Lyme borreliosis from 1987 to 1992. Basic criteria for the inclusion of our patients in the study were: tick bite, erythema migrans and antibodies to B. burgdorferi in each patient's serum. Various clinical manifestations were found un 1034 (94.6%) patients out of whom 829 (80.2%) had a history of tick bite, 901 (87.1%) had erythema migrans and 217 (21.0%) had serologic confirmation of the diagnosis. Inapparent infection was discovered in 59 (5.4%) patients. Other Types of skin changes (II and III stage) were found in 123 (11.9%) patients. The disease resulted in neurologic, joint and cardiac manifestations in somewhat lower percentage of patients (6.3%, 6.6% and 1.5%, respectively). In the three-year period (1990-1992) microscopic examination of the ticks (Ixodes ricinus) collected at several green areas of Belgrade confirmed the presence of B. burgdorferi in 29.1 per cent.

[Skin changes in patients with Lyme borreliosis]. / Kozne promene u obolelih od Lyme borreliosis.

In introduction some clinical characteristics of Erythema migrans, Borrelia lymphocytoma and acrodermatitis chronica atrophica has been described. The importance of atypical forms of Erythema migrans and the difficulties in differential diagnosis of cutaneous manifestation has been stressed. In a prospective, and partly retrospective investigation of 1292 persons with tick bites, signs of Lyme borreliosis have been found in 18.96%. Number of such persons seen in dermatology wards is rising, and 18.2% of these are children less than 15 years of age. Patients seen in dermatology are mostly women (56.5%:43.5%). Nearly half of the patients with Erythema migrans did not known that they had a tick bite (42.5%). Lyme borreliosis was manifested mainly as Erythema migrans, 89% of patients. Borrelia lymphocytoma was encountered in 2%, and Acrodermatitis chronica atrophicans in 0.4% of patients, significantly less than in other reports. Sclerotic skin lesions were found in 4.1% of patients, and some macular and urticarial lesions were recorded. An incubation period generally less than three weeks preceded to skin manifestations, but in some patients this period could not be recorded. Skin lesions were located on lower extremities in 50.4% of patients, trunk in 25.5%, and upper extremities in 10.5% of patients. In 87% of patients skin lesions lasted less than three weeks. Symptoms were present in 62% of patients. Seropositivity to Borrelia burgdorferi has been found in 10.2% of patients, mostly three weeks after the tick bite.

[Lyme disease in dermatology practice]. / Lajmska bolest u praksi dermatologa.

The authors studied a group of 77 patients with Erythema migrans. They were treated at the City Institute for Skin and Venereal Disease in Belgrade, over a five-year period (1988-1992). A tick bite at the site where Erythema migrans later appeared was recalled by 44 (57.1%) of the patients. The interval between tick bite and Erythema migrans varied from 1 to 45 days. The indirect IF test was seropositive in 11.6% of the Erythema migrans patients. In the present study the authors emphasize the importance of early treatment in order to minimize the longterm morbidity.

[Epidemiologic characteristics and serologic findings in erythema migrans]. / Epidemioloske karakteristike i seroloski nalaz kod erythema migrans.

Our three-year research covered 417 patients with erythema migrans, of both sexes and all age groups. Among them 87.3% had a history of tick bite. Average attachment of tick to a patients skin was two days. Diameter of erythematous lesions was 1-50 cm (with an average of 15.1 cm). Magnitude of the lesion does not correlate with the further development of the Lyme disease. IFA test detected antibodies against Borreliae burgdorferi in 27.0% of our patients.

Basic fibroblast growth factor induction of granulosa cell tissue-type plasminogen activator expression and oocyte maturation: potential role as a paracrine ovarian hormone.

Gonadotropin-induced ovulation is associated with oocyte maturation and preovulatory increases of tissue plasminogen activator (tPA) expression. Basic fibroblast growth factor (bFGF), an angiogenic factor found in many organs including the ovary, modulates steroidogenesis in granulosa cells and increases PA activity in endothelial cells. Here studies were performed to examine the possible roles of bFGF as an intragonadal regulator of tPA expression and oocyte maturation. In cultured granulosa cells, bFGF caused a time-dependent (onset at 24 h) and dose-dependent (ED50 = 0.6 nM) increase (up to 5-fold) in tPA enzyme activity as measured by the fibrin overlay technique. Northern blot hybridization also revealed that treatment of cells with bFGF (2 nM) increased the level of the 22S tPA messenger RNA. Slot blot analysis indicated that the effects of bFGF were time dependent and dose dependent; tPA message levels increase before tPA activity levels. bFGF (0.6 nM) also significantly increased granulosa cell cAMP production in both the absence and presence of a phosphodiesterase inhibitor. In follicle-enclosed oocytes incubated for 24 h in media with or without increasing concentrations of LH or bFGF, germinal vesicle breakdown was observed in only 1.6% of controls, but 85% of LH (1 microgram/ml)-treated oocytes underwent maturation. Likewise, bFGF induced germinal vesicle breakdown (10-80%) over a dose range of 0.6 to 333 nM. In the same follicles, bFGF, like LH, also stimulated prostaglandin E production. These results, coupled with the identification of bFGF in growing follicles, suggest that bFGF acts as an intraovarian inducer of granulosa cell tPA gene expression and oocyte maturation.