Alkali Metal Cations Bonding to Carboxylate Anions: Studies using Mass Spectrometry and Quantum Chemical Calculations.

Data on the gas-phase energetics of anion/cation interactions are relatively scarce. In this work, gas-phase alkali metal cation basicity (AMCB) scales were established for a series of 15 benzoate ions XC6H4COO- with Li+, Na+, K+, Rb+, and Cs+ on the basis of mass spectrometry experiments and high-level calculations. A wide range of electron-donating and electron-withdrawing substituents were included in the study. The thermochemical values were calculated by ab initio methodologies and extrapolated to the complete basis set limit. For each metal cation, the experimental relative cation basicity values of the anions were established quantitatively by applying the Cooks' kinetic method to the cation-bound heterodimers [(XC6H4COO-)M+(YC6H4COO-)]-, generated by electrospray ionization. The self-consistency of these AMCB scales was ascertained by multiple overlap of the individual relative basicities. In parallel, the proton gas-phase basicities (GBs) of the benzoate anions (gas-phase acidities of the respective benzoic acids) were calculated in order to compare the results of the theoretical method with known experimental GB values. The experimental and calculated GB values agree quite accurately (average absolute deviation = 3.2 kJ mol-1). The relative experimental AMCB scales and the absolute calculated AMCB scales are highly correlated, and the two sets agree by better than 4 kJ mol-1. It is also demonstrated that the five series of calculated AMCBs are highly correlated with the calculated GB.

Parametrization of nanoparticles: development of full-particle nanodescriptors.

While metal oxide nanoparticles (NPs) are one of the most commonly used nanomaterials, the theoretical models used to analyze and predict their behavior have been mostly based on just the chemical composition or the extrapolation from small metal oxide clusters' calculations. In this study, a set of novel, theoretical full-particle descriptors for modeling, grouping or read-across of metal oxide NP properties and biological activity was developed based on the force-field calculation of the potential energies of whole NPs. The capability of these nanodescriptors to group the nanomaterials acoording to their biological activity was demonstrated by Principal Component Analysis (PCA). The grouping provided by the PCA approach was found to be in good accordance with the algal growth inhibition data of well characterized nanoparticles, synthesized and measured inside the consortia of the EU 7FP framework MODERN project.

A data acquisition system for long-term monitoring of physiological and video signals.

We developed a system for interleaving digitized physiological signals and video images of subjects onto digital media in a standard file format. The system consists of a framegrabber used to digitize video signals, a microcomputer used to digitize analog signals and send the resulting signals over a parallel interface, and a host laboratory computer to gather and store the video and analog data in an interleaved format as a single file. The system allows for digital storage, search and display of video signals concurrently with physiological signals.

Investigation of unwanted images caused by intraocular lenses.

A widely circulated paper by IOLAB Corporation describing unwanted images inadvertently presented various images that could not exist with a centered intraocular lens as was claimed in the study. I repeated the IOLAB experiments and found that artifacts within the Gullstrand eye model, which was used in the IOLAB study, were the cause of these images. I also found that a myopic eye will see a collimated light or point source as a mottled cluster of bright spots which can be simulated, in an eye model, by a faceted corneal lens. From this observation, I learned that people can see their own cataracts when looking at a distant light.

Prevalence of cutaneous disease in patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex.

Ninety adult patients with acquired immunodeficiency syndrome (AIDS) and 27 with AIDS-related complex were seen consecutively, when available, either as inpatients or in AIDS clinics and given complete cutaneous examinations. Skin disease was common both in patients with AIDS and in those with AIDS-related complex. The most common cutaneous findings were candidiasis in 55 patients (47.0%), dermatophytosis in 35 (30%), herpes simplex infections in 26 (22%), molluscum contagiosum in 11 (9%), seborrheic dermatitis in 37 (32%), and acquired ichthyosis or xerosis in 36 (30%). Several cutaneous conditions previously reported in association with AIDS were infrequently seen: Psoriasis was seen in only one patient, and deep fungal infections and basal and squamous cell carcinomas were seen in none. No significant differences were noted in the prevalence of skin disease between patients with AIDS and those with AIDS-related complex, although xerosis and ichthyosiform skin changes tended to be more common in those with AIDS. The yellow nail syndrome and "a papular eruption" associated with AIDS were seen. Skin diseases also tended to be widespread and severe in the patients studied.

Penile premalignant fibroepithelioma of Pinkus.

A 63-year-old man with a premalignant fibroepithelioma of Pinkus on the base of his penis is presented. Penile premalignant fibroepitheliomas have not, to the best of our knowledge, been previously described. Because fibroepithelioma of Pinkus is a morphological variant of a basal cell epithelioma, we believe that clinically benign fibroma-like lesions appearing on the penis should be biopsied to rule out the presence of this premalignant lesion.

Inhibition of cell proliferation and protease activity by cartilage factors and heparin.

Proliferating rat smooth muscle cells and fibroblasts have membrane-associated protease activity. High concentrations of heparin inhibited membrane-associated protease activity and cell proliferation, while low concentration of heparin promoted smooth muscle cell proliferation. The inhibition of protease activity and proliferation was abolished when heparin was treated with protamine sulfate or when acid treated fetal calf serum was used. Heparin required the presence of an acid labile factor(s) in serum for the inhibition of protease activity and proliferation. Heparin and antithrombin III in the presence of acid-treated fetal calf serum did not inhibit cell proliferation or protease activity. Cartilage factors isolated from bovine nasal cartilage containing trypsin inhibitory activity, but not papain inhibitory activity, inhibited rat smooth muscle and fibroblast proliferation and surface associated protease activity. The cartilage factors did not require acid-labile components in the fetal calf serum for the inhibitory activity. The inhibitory activity due to heparin and cartilage factors was not permanent under our experimental condition. Protein synthesis was not inhibited by heparin or the cartilage factors. In rat smooth muscle cells and fibroblasts, the expression of surface-associated protease activity was related to the proliferative state of the cells. Surface protease activity was only present on proliferating cells. When surface protease activity was inhibited by high concentrations of heparin in the presence of an acid-labile serum component(s) or cartilage factors, cell proliferation was also inhibited.

The role of a directly observed, continuous case conference in the training of child psychiatrists.

The directly observed, continuous case conference is studied in depth as a format for teaching child psychotherapy. The effects of group dynamics, direct observation, and the specific case on the processes of therapy, learning, and supervision are examined. Six guidelines are set forth to maximize the effectiveness of the conference.

Mucocutaneous eruptions due to antiepileptic drug therapy in children.

Three children with bullous erythema multiforme and 1 with toxic epidermal necrolysis associated with antiepileptic drug therapy are described. One patient is unique because of seven mucocutaneous eruptions caused by three classes of antiepileptic drugs. Lymphocyte stimulation by antiepileptic drugs could not be demonstrated in the 2 patients in whom appropriate studies were performed, and no precipitating antibodies to antiepileptic drugs were found. Observation of four diagnostic and therapeutic principles, which are illustrated by the course of our patients, may reduce the incidence of life-threatening mucocutaneous eruptions and simplify the long-term management of individuals in whom such reactions occur.

Characterization of a chemotactic and cytotoxic proteinase from human skin.

A proteinase (EC 3.4.-.-) active at physiological pH has been isolated from human skin utilizing gel filtration and affinity chromatography techniques. The proteinase has a molecular weight of approx. 28 000 and it is inhibited by alpha 2-macroglobulin, alpha 1-antitrypsin, C-1 inactivatory, soybean trypsin inhibitor and diisopropyl fluorophosphate. 2njection of 1 ng of purified proteinase into rabbit skin induces polymorphonuclear leukocyte infiltration of the cutis. Inhibition of enzyme activity with diisopropyl fluorophosphate inhibits the chemotactic effect. Addition of 0.2 microgram/ml of purified proteinase to fibroblast cultures kills the cells within minutes. This proteinase may play a significant role in modulating the inflammatory response after cellular injury.

Relationship between cell surface protease activity and doubling time in various normal and transformed cells.

A sensitive method for measuring cell surface and secreted protease activity utilizing 3H-labelled casein is described. The method is based upon proteolytic degradation of the casein substrate into trichloracetic acid soluble 3H-labelled peptides. Utilizing the radioassay we found that all cultured cell lines examined contain cell surface proteolytic activity which is not secreted into the media. The protease activity was found to be due to protease(s) other than plasminogen activator or plasmin. A comparison of surface protease activity of normal and transformed mouse epidermal cells indicated that the transformed cells contained approximately 3--1 times more proteolytic activity than the normal cells. Surface protease activity was also correlated with the doubling times of various cultured cells. The results indicated that cultured cells with doubling times of greater than three days possess less surface protease activity than cells with shorter doubling times. In order to determine changes in the levels of surface protease activity during the cell cycle several cell lines were synchronized. In synchronized rabbit aortic fibroblasts, mouse transformed epidermal cells and human melanoma cells, a marked increase in surface protease activity was observed during or before mitosis. The protease levels decreased following mitosis. The results suggest that in culture, cell surface protease(s) may be important factor in regulating the rate of cell growth.