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Notes: The H− negative ion thermal energy measured using the two-laser-pulse photodetachment technique is reported to be in the range from 0.1 to 0.7 eV for various conditions of volume ion source operation (pressure−from 2 to 7 mTorr, discharge current−from 1.5 to 20 A). The hydrogen pressure has a significant effect in lowering the negative ion temperature, while the increase of the discharge current leads to a rise in T−. It is found that T− is a fraction of the electron temperature, Te. This fraction is strongly dependent on the gas pressure. T− scales linearly with the electron temperature and exceeds the highest values predicted by the theory of dissociative attachment. The possible mechanisms for H− ion heating are discussed.

Notes: A new technique using laser induced photodetachment has been developed for measuring the negative ion temperature in H− and D− sources. Using this technique, we have investigated the dependence of the negative ion temperature on source parameters such as pressure, discharge current, and electron temperature. Simultaneous measurements of negative ion density, temperature, and extracted current lead to the conclusion that the extracted negative ion current is, at most, equal to the thermal flux.

Notes: Hyaluronic acid (HA), a high molecular weight glycosaminoglycan of the extracellular matrix involved in growth, inflammation and wound healing, also contributes to the hydration and plastic properties of skin. Several drug and cosmetic formulations contain HA. We have initiated investigations that explore whether it is possible, by topical application, to modulate endogenous HA levels in skin. We developed a model epidermal culture system that exhibited a differentiated stratum corneum, and expressed HA and the HA receptor CD44, in a pattern similar to that observed in intact skin. Such in vitro skin equivalents are useful models for investigating the effect of topical drugs. HA and bacterial hyaluronidase were applied to the in vitro skin equivalent and to human skin. Their effects on endogenous HA and CD44 expression were examined using histochemical analysis. Topical HA treatment had no significant effect on HA or CD44 expression in either system. However, hyaluronidase decreased HA and CD44 expression in a dose-dependent manner in both the epidermal culture system and in skin. Apparently, HA is not able to permeate the epidermal culture system or human skin to a significant degree, but bacterial hyaluronidase does permeate both human skin and the culture system, depleting HA and decreasing CD44 expression. These effects were more prominent in the dermal than in the epidermal layers, suggesting that marked differences in HA metabolism exist in these two skin compartments. The ability of hyaluronidase to permeate the stratum corneum suggests that topical application may, additionally, be useful as a clinical modality.

Notes: Anomalously fast ion heating has been observed in the Caltech Encore tokamak [Phys. Rev. Lett. 59, 1436 (1987)], with the use of laser-induced fluorescence. This heating was found to be independent of electron temperature, but was well correlated with the presence of large-amplitude drift-Alfvén waves. Evidence is presented that suggests that the heating is stochastic and occurs when the ion displacement due to polarization drift becomes comparable to the perpendicular wavelength, i.e., when k⊥ (mik⊥ φ0/qB2)∼1. Stochastic heating may also be the cause of the anomalously high ion temperatures observed in reversed-field pinches.

Notes: Background : Meal ingestion has been suggested to reduce susceptibility to the development of gastric tachyarrhythmia, the abnormal activity of the stomach that frequently accompanies nausea.Aim : To determine the types of meal that are most effective in preventing the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness provoked by a rotating optokinetic drum.Method : Participants received a carbohydrate beverage, a protein-predominant beverage or nothing immediately before exposure to the rotating drum. Subjective symptoms of motion sickness and electrogastrograms were collected during a 6-min baseline period and a subsequent 16-min drum rotation period.Results : Subjective symptoms of motion sickness scores were significantly more severe during the no-meal condition than during either the protein or carbohydrate condition. Central, peripheral and, to some extent, gastrointestinal symptoms were more severe during the carbohydrate condition than during the protein condition. Gastric tachyarrhythmia increased significantly less from baseline to drum rotation during both the protein and carbohydrate conditions than during the no-meal condition.Conclusions : Liquid protein-predominant meals were most effective in suppressing both the development of gastric tachyarrhythmia and the entire spectrum of motion sickness symptoms, including nausea.

Notes: Background : Cystic fibrosis causes exocrine pancreatic insufficiency, leading to malabsorption. Supplemental pancreatic enzyme therapy alleviates the concomitant malnutrition experienced by cystic fibrosis patients. It is recognized that patients experience variations in clinical response to different brands of enzymes. This has prompted the US Food and Drug Administration to require that enzyme supplements be subjected to New Drug Applications.Aim : To investigate the safety and efficacy of supplemental pancreatic enzyme therapy in cystic fibrosis subjects.Methods : We compared two doses of one formulation of enteric-coated pancreatic enzymes: Ultrase MT12 (12 000 lipase units per capsule) and Ultrase MT20 (20 000 lipase units per capsule), to placebo in two separate safety and efficacy studies.Results : Mean total fat, protein and carbohydrate intake did not differ significantly between the groups. A significant difference in both fat and protein absorption occurred with the enzyme therapy groups. The Ultrase MT12 and Ultrase MT20 groups experienced a mean fat and protein absorption 79.4% and 83.8%, and 87.3% and 88.6%, respectively. No adverse events related to study drug were reported.Conclusions : This study further supports the use of enzymes to treat pancreatic insufficiency in cystic fibrosis. Excellent fat and protein absorption was achieved with minimal adverse events and safe doses.

Notes: Background  Scleroderma, or systemic sclerosis, is characterized by aberrations of extracellular matrix deposition. These changes parallel early stages of wound healing when increased deposition of hyaluronan (HA) and collagen occur. Both processes result ultimately in the formation of fibrotic scar tissue. Activities of HA synthase and hyaluronidase, the enzymes that synthesize and degrade HA, are critical in HA turnover. Both become elevated whenever increased matrix deposition occurs. HA deposition occurs early in wound healing, and increases are documented in the circulation of scleroderma patients. We postulated that elevated HA and hyaluronidase may both be indicators of early-stage disease in scleroderma, in parallel with early changes observed in wound healing. In an attempt to reduce HA accumulation and the associated fibrosis in scleroderma tissues, topical and intravenous hyaluronidase administrations have been used in the past as treatment modalities, with occasional success. This also suggested that hyaluronidase enzyme activity is involved in the disease process. It is now recognized that the hyaluronidases constitute an enzyme family. The somatic hyaluronidase Hyal-1 is the only activity present in human serum.Objectives  To determine levels of HA and Hyal-1 in the sera of scleroderma patients at various stages of their disease.Methods  Levels of HA and Hyal-1 activity were determined in 25 scleroderma patients. Subjects were separated into two groups, those in the early stage with duration of disease of 2 years or less, and late-stage patients with disease duration of more than 2 years.Results  In early-stage scleroderma, levels of HA were elevated significantly, as predicted, in comparison with late-stage patients and controls. Late-stage levels of HA were comparable with those found in control sera. By contrast, levels of Hyal-1 activity were normal in early-stage patients, similar to those in controls, but were decreased in late-stage patients, falling even below those of controls.Conclusions  We have confirmed that circulating levels of HA are elevated in scleroderma, but show for the first time that such elevations occur predominantly in early-stage disease. Patients with late-stage disease have decreased serum Hyal-1 activity, perhaps reflecting decreased levels of HA turnover. This study also represents the first time that hyaluronidase activity levels have been determined in scleroderma patients.

Notes: Sixty-six ITI implants placed in the mandible of 33 edentulous elderly patients (mean age: 69 years) were observed longitudinally for 5 years. The implants served as overdenture anchorage either by means of a connecting bar or single spherical attachments. During the study period, 2 implants failed (one because of a peri-implant lesion and one because of a fracture) and had to be removed. At the beginning of the study, all implants were osseointegrated and had successfully been in function for 335 months. Oral hygiene practices and the peri-implant mucosal status were assessed according to the criteria of conventional periodontal parameters. Approximately 50% of the implants had been installed into lining mucosa and hence were to surrounded by keratinized mucosa. The peri-implant mucosal tissue was maintained healthy during the whole observation period, and no or only minimal loss of attachment was observed. The probing depths averaged approximately 3 mm. At the end of the study, orthopantomographic radiographs were obtained from all patients to assess the peri-implant bony structures. Small local angular bony defects were detected on 16 implants (22%) in 12 patients. Slightly increased probing depths were observed when angular bony defects were present. Loss of attachment was significantly less frequent when the implants had been placed following a prolonged period of edentulousness (〈5 years). This study demonstrated that advanced age, reduced dexterity of elderly patients and environmental conditions of overdentures do not represent a 1 higher risk for the development of peri-implant lesions.