Immunocytochemical localization of chymase to cytoplasmic vesicles after rat peritoneal mast cell stimulation by compound 48/80

The subcellular events responsible for release of mediators by mast cells may help to clarify roles for mast cells in health and disease. In this study we show that the granule-associated protease chymase is also within cytoplasmic vesicles in appropriately stimulated rat peritoneal mast cells. Rat peritoneal mast cells were recovered before or 1-10 sec after exposure to the secretogogue compound 48/80 (10 micrograms/ml) and then were examined by radioimmunoassay to quantify histamine release or were processed, using routine methods for postembedding immunoelectron microscopy, to identify the subcellular localization of chymase. In comparison to unstimulated cells, compound 48/80 stimulated cells in two independent experiments showed an increase (15%, 28%) in the surface area of the cell and a decrease (12%, 6%) in the surface area of the total granule compartment before degranulation channel formation. These global cellular changes occurred in a background of transient but significant (p < 0.01) increases in the area and number of chymase-immunoreactive vesicles per microns2 cytoplasm. These changes were detectable at 5 or 7 sec after stimulation with compound 48/80 but returned to near prestimulation levels by 9 or 10 sec after addition of compound 48/80 (total cumulative histamine release was 28% by 8 sec and 47% by 14 sec). These observations suggest that vesicles participate in the early stages of regulated secretion of chymase from rat peritoneal mast cells.     

A 10 Gbit/s OEIC photoreceiver using InP/InGaAs heterojunction bipolar transistors

Metal organic molecular beam epitaxy (MOMBE) was successfully used for the first time to realise a high speed monolithic photoreceiver. Incorporating an InGaAs pin photodetector followed by a transimpedance preamplifier circuit implemented with InP/InGaAs heterojunction bipolar transistors (HBTs), the OEIC photoreceiver had a bandwidth of 6 GHz and a midband transimpedance of 350 Omega . In a system experiment performed at 10 Gbit/s, the receiver exhibited a sensitivity of -15.5 dBm for a bit error rate of 10/sup -9/ at a wavelength of 1.53 mu m. This is the first demonstration of operation of a long wavelength OEIC photoreceiver at this speed.<>     

The effect of physical exercise on the response to exertion in the elderly

BACKGROUND: A decrease in adaptation to exertion has been observed as age progresses. Although this decline may also be affected by factors such as health conditions and age, physical inactivity related to sedentary behaviour plays a dominant role. METHODS: In order to evaluate the influence of physical activity on cardiovascular response to exertion in the elderly, 4 groups of 22 subjects each were submitted to maximal electrocardiographic exercise test on a cycloergometer (multistage program with 30 Watts x 3 min. steps). All subjects were male. The composition of the groups was as follows: 1) veteran long distance runners (mean age: 71 +/- 5.4); 2) sedentary veterans (mean age: 69.8 +/- 3.9); 3) young long distance runners (mean age: 25.4 +/- 4.3); 4) sedentary young adults (mean age: 25.8 +/- 3.9). The endurance athletes, well fitted to competition, had been practicing sport activity for at least 3 years. RESULTS: Heart rate, arterial systolic and diastolic blood pressure were recorded; mean blood pressure and double product were calculated at baseline and at the climax of the stress test; furthermore, total and maximal watts were recorded. For each of the parameters, Student's t test for non-paired observations were used to evaluate statistical differences amongst the four groups. The most interesting result arises in the comparison between veteran long distance runners and sedentary young adults: between the two groups no statistically significant differences in workload, expressed as total watts (1649.55 +/- 296.32 vs 1650.00 +/- 446.32; p = NS) and maximal watts (175.91 +/- 19.19 vs 173.18 +/- 24.38; p = N.S.), were observed. On the contrary, highly significant differences in both total (p < 0.01) and maximal (p < 0.01) watts were noticed by comparing long distance runners and sedentary subjects of the same age. CONCLUSIONS: These data support the hypothesis that the progressive reduction in physical activity, which is usually observed in aging, is the major determinant of exercise deconditioning in the elderly.     

Intracranial actinomycosis in juvenile patients. Case report and review of the literature

A case of actinomycotic brain infection in a juvenile patient is described. Cases of actinomycosis affecting the head and neck are rare, particularly in juvenile patients. In this case complete resolution of the infection was achieved by means of surgical treatment and prolonged antibiotic therapy. The authors emphasize the importance of a combined approach for treatment of this unusual brain infection and stress the difficulties involved in the diagnosis of this pathology.     

The nuoM arg368his mutation in NADH:ubiquinone oxidoreductase from Rhodobacter capsulatus: a model for the human nd4-11778 mtDNA mutation associated with Leber''s hereditary optic neuropathy

The patellar tendon reflex (PTR) and simple visual reaction time (RT) were fractionated and compared in 40 subjects with developmental coordination disorder (DCD) and normal coordination (NC) in two age groups. Four equal groups of subjects, 6 years DCD (6DCD), 6 years NC (6NC), 9 years DCD (9DCD), and 9 years NC (9NC) were compared using ANOVA for the main effects of coordination and age. PTR and its components of reflex latency and motor time were not significantly affected by the level of coordination; however, a significant coordination by age interaction (p < .05) revealed an increased motor time in the 6DCD group. RT, premotor time, and motor time were all significantly (p < .05) increased in children with DCD; the increased RT and premotor time support earlier findings, whereas the increased motor time has not previously been found. These findings suggest that the processing of reflexive and volitional responses by children with DCD differs from that of their NC peers.     

Performance of eight-channel OEIC p-i-n/HBT receiver array in8×2.5 Gb/s WDM transmission system

The performance of an eight-channel, 2.5 Gb/s OEIC photoreceiver array in an eight-wavelength long-distance WDM testbed is described. The sensitivity penalties due to crosstalk and transmission are measured, and the source of crosstalk is investigated. Channel sensitivities range from -25.4 to -26.2 dBm after transmission through 720 km of standard fiber, with transmission penalties ranging from 0.3 dB to 1.0 dB. When the power in each of seven interfering channels is 5 dB above sensitivity, the maximum crosstalk penalty suffered by an individual channel does not exceed 1 dB. These experiments are the first comprehensive characterization of monolithic receiver arrays for crosstalk performance under multichannel operation in a realistic system environment     

Analysis of the T cell receptor repertoire in rheumatoid arthritis

BACKGROUND AND AIMS OF THE STUDY: Valve repair, where suitable, is the preferred option in patients who require mitral surgery. A number of studies have shown excellent long-term results, but most were undertaken in tertiary referral centers with a high throughput of patients. METHODS: We present our experience in 60 patients, aged 60 +/- 14 years, undergoing repair between 1984 and 1993. Most patients (83%) were in New York Heart Association (NYHA) class II or III at the time of surgery; 27% had concomitant ischemic heart disease. Almost all (98%) had posterior leaflet repair and 18% had anterior leaflet repair. Eight surgeons each performed a mean of 7.5 operations during this period. RESULTS: The 30-day mortality rate was 3.3%. There were seven late deaths. Five patients underwent reoperation for mitral regurgitation (two early, three late). At six years, 60% of patients were alive, or free of stroke or reoperation. Late follow up was obtained in 45 of 47 surviving patients: 95% were in NYHA class I or II; one-third were on anticoagulants for atrial fibrillation; 90% had mild (or less) mitral regurgitation on echocardiography. CONCLUSIONS: These data show that most patients have a very good outcome from valve repair surgery and encourage the trend towards operating earlier in the course of the disease. Adverse outcomes occurred mainly in patients who were highly symptomatic at the time of surgery. The high proportion of patients on postoperative anticoagulants underscores the importance of operating before atrial fibrillation becomes permanent.     

Quantum functional devices: resonant-tunneling transistors,circuits with reduced complexity, and multiple valued logic

Recent advances in the area of quantum functional devices are discussed. After a discussion of the functional device concept, resonant-tunneling bipolar transistors (RTBTs) with a double barrier in the base region are described. Design considerations for RTBTs with ballistic injection and the first observation of minority-electron ballistic RT are presented. RTBTs using thermionic injection and exhibiting a high peak-to-valley ratio at room temperature in the transfer characteristics are also described. Multiple-state RTBTs and their DC and microwave performance are then discussed. Circuit applications of RTBTs also are discussed. It is shown that RTBTs allow the implementation of many analog and digital circuit functions with a greatly reduced number of transistors and show considerable promise for multiple-valued logic. Experimental results on frequency multipliers and parity bit generators are presented. Analog-to-digital converters are memory circuits are also discussed. Two novel superlattice-base transistors are reported. Negative transconductance is achieved by suppression of injection into minibands. Gated quantum-well RT transistors are also discussed     

Advanced components and sub-system solutions for 40 Gb/s transmission

With the commissioning of the latest 10-Gb/s systems, vendors are now in the process of developing architectures for their next-generation products. 40-Gb/s components and subsystems are currently in development to address the necessities of these next-generation systems. The top three challenges associated with 40-Gb/s transmission are optical signal-to-noise ratio, dispersion, and high-speed components. In order to realize 40-Gb/s transmission, new component and subsystem developments are crucial. This paper reviews the latest transmission technologies and dispersion compensation techniques developed to fulfill 40-Gb/s transmission system requirements.