Determination of plasma ET-1 by RIA--risks and limitations

Plasma concentrations of the vasoconstrictor peptide endothelin-1 (ET-1) were determined in nonobese healthy subjects as well as in unspecified patients using three different commercially available radioimmunoassays (RIAs) and the respective recommended prepurification procedures. Depending on the antibody and extraction procedure applied different ET-1 concentrations were measured in identical plasma samples. Thus, this study clearly documents that ET-1 concentrations measured in plasma samples represent apparent concentrations which have to be interpreted with caution.     

Generalized ideal reference cycle for regenerative refrigeration: Part 2. Adiabatic systems

A generalized ideal reference cycle for regenerative refrigeration systems is discussed. The cycle has adiabatic processes of compression and expansion. Cyclic heat addition to and rejection from the cycle occur at constant pressure or constant volume immediately preceding the regenerative thermal processes. These are assumed to occur partly at constant volume, partly at constant pressure. Equations are developed for cycle work, heat lifted, coefficient of performance and the pressure ratio: mean effective/maximum cycle pressures. Various special cases are deduced from the generalized analysis including the pseudo-Stirling and pseudo-Ericsson cycles.Results are presented for the Stirling and pseudo-Stirling cycles to illustrate the effect of volume compression ratio and regenerative effectiveness on the cycle Coefficient of Performance. The pressure ratio p_mean/p_max for the same two cycles are compared to a function of the volume compression ratio.     

An array processor for general purpose digital image compression

A new VLSI processor (DIP chip) for image compression is presented which combines principles of multipipeline and array processing. The device is not specific to any one image compression algorithm and can be regarded as a general purpose processor. The chip has been implemented using a CMOS 1.0-μm process on a 14.4×13.5-mm² die. An internal clock frequency of 40 MHz results in 1.2×10⁹ operations/s on 8-bit data. Solutions to problems associated with the large bandwidth required, for both image data and instruction streams, is the main aim of the paper. The necessary problem of increasing the array clock frequency relative to the input/output clock frequency without the need for a large on-chip instruction cache or fast external clock speeds is also addressed     

Alveolar bone grafting in unilateral complete cleft lip and palate patients

Autogenous bone graft of an alveolar cleft area has the following advantages: (1) assistance in the closure of buccoalveolar oronasal fistula; (2) provision of bony support for unerupted teeth and teeth adjacent to the cleft; (3) formation of a continuous alveolar ridge to facilitate orthodontic correction of malocclusion; (4) supporting the nostril floor and alar base to improve nasal aesthetics. It has been well accepted in most craniofacial centers as routine procedure in cleft lip and palate rehabilitation. A new surgical technique for alveolar bone grafting has been introduced to the Chang Gung Craniofacial Center since July 1991. It provided a good exposure of the alveolar cleft, primary closure of the fistula and adequate volume of bone graft. A review of 27 consecutive alveolar bone grafting procedures performed in unilateral cleft lip and palate patients from July 1991 to June 1992 was presented. Patients have been followed up for at least 6 months. The alveolar bone graft was evaluated clinically and radiologically at one week, six months and one year after the surgery. The preliminary results indicated that the new surgical technique produced less chance of recurrent fistula, good postoperative gingival height, and improvement of nasal aesthetics. Based on the results of this new study we strongly advocate the use of this new surgical technique.     

Adenovirus-mediated p53 gene transfer in patients with advanced recurrent head and neck squamous cell carcinoma

PURPOSE: Standard therapies of head and neck squamous cell carcinoma (HNSCC) often cause profound morbidity and have not significantly improved survival over the last 30 years. Preclinical studies showed that adenoviral vector delivery of the wild-type p53 gene reduced tumor growth in mouse xenograft models. Our purpose was to ascertain the safety and therapeutic potential of adenoviral (Ad)-p53 in advanced HNSCC. PATIENTS AND METHODS: Patients with incurable recurrent local or regionally metastatic HNSCC received multiple intratumoral injections of Ad-p53, either with or without tumor resection. Patients were monitored for adverse events and antiadenoviral antibodies, tumors were monitored for response and p53 expression, and body fluids were analyzed for Ad-p53. RESULTS: Tumors of 33 patients were injected with doses of up to 1 x 10(11) plaque-forming units (pfu). No dose-limiting toxicity or serious adverse events were noted. p53 expression was detected in tumor biopsies despite antibody responses after Ad-p53 injections. Clinical efficacy could be evaluated in 17 patients with nonresectable tumors: two patients showed objective tumor regressions of greater than 50%, six patients showed stable disease for up to 3.5 months, and nine patients showed progressive disease. One resectable patient was considered a complete pathologic response. Ad-p53 was detected in blood and urine in a dose-dependent fashion, and in sputum. CONCLUSION: Patients were safely injected intratumorally with Ad-p53. Objective antitumor activity was detected in several patients. The infectious Ad-p53 in body fluids was asymptomatic, and suggests that systemic or regional treatment may be tolerable. These results suggest the further investigation of Ad-p53 as a therapeutic agent for patients with HNSCC.     

Prooxidant effects of ferrous iron, hemoglobin, and ferritin in oil emulsion and cooked-meat homogenates are different from those in raw-meat homogenates

Oil emulsion and raw and cooked tissue homogenates were used to determine the mechanisms of various iron forms on the catalysis of lipid peroxidation. Flax oil (0.25 g) was blended with 160 mL maleate buffer (0.1 M, pH 6.5) to prepare an oil emulsion. Raw or cooked turkey leg meat was used to prepare meat homogenates. Samples were prepared by adding iron from each of the various sources, reactive oxygen species, or enzyme (xanthine oxidase and superoxide dismutase) systems into the oil emulsion or meat homogenates. In oil emulsion and cooked-meat homogenates, ferrous iron and hemoglobin had strong prooxidant effects, but ferritin became prooxidant only when ascorbate was present. Hemoglobin and ferritin had no prooxidant effect in raw-meat homogenates. The status of heme iron and the released iron from hemoglobin had little effect on the prooxidant effect of hemoglobin in oil emulsion and cooked meat homogenate systems. The prooxidant effect of ferrous iron in oil emulsion and cooked-meat homogenates disappeared in the presence of superoxide (.O2-), H2O2, or xanthine oxidase systems. In raw-meat homogenates, however, ferrous had strong prooxidant effects even in the presence of .O2-, or H2O2. The status of free iron was the most important factor in the oxidation of oil emulsion and cooked-meat homogenates but the impact in raw-meat homogenates was small.