Subspecific differentiation of Burkholderia cepacia isolates in cystic fibrosis

While ceramide has emerged as a potent signal transducer, inconsistencies in the kinetics of ceramide generation, or its absence, in response to stimuli have led to confusion and skepticism as to its potential role in apoptosis or proliferation. Here we show that in U937 and HL60 myeloid leukemia cells and in normal skin fibroblasts, cell-permeant ceramides can trigger neutral sphingomyelinase activation, sphingomyelin hydrolysis, and endogenous ceramide generation regardless of Bcl2 overexpression. These observations identify neutral sphingomyelinase as a novel target for ceramide and show that this positive feedback mechanism is responsible for signal propagation, as exemplified by mitogen-activated protein kinase activation in daunorubicin-treated cells. This study provides insight into a fundamental process of cell biology. Indeed, such a sustained ceramide-mediated signal throughout the apoptotic process would ensure self-destruction, perhaps by overriding evolutionary conserved primal cell survival mechanisms.     

The Hephaestus Smart Wheelchair system

The Hephaestus Smart Wheelchair System is envisioned as a series of components that clinicians and wheelchair manufacturers will be able to attach to standard power wheelchairs to convert them into "smart wheelchairs." A prototype of the system has been developed and mounted on an Everest and Jennings Lancer2000 wheelchair. The prototype bases its navigation assistance behavior on the behavior developed for the NavChair Assistive Wheelchair Navigation System, but the underlying hardware and software are being designed to facilitate commercialization. This paper describes our design goals for the Hephaestus system and discusses the current status of the system prototype as well as plans for future work.     

Stability of N-Acetylglutamine and Glutamine in Aqueous Solution and in a Liquid Nutritional Product by an Improved HPLC Method

ABSTRACT: Stability of N-acetylglutamine (NAQ) in aqueous solutions from pH 2.0 to 8.0 and at 100 °C and in a liquid nutritional product was compared to glutamine using an improved HPLC method that allowed quantitation of degradation products. NAQ was stable for 6 mo at pH > 4.0 at about 20 °C. N-acetylglutamic acid, the major degradation, was found in samples stored for ≥ 2 wk. At pH 4.0 and higher, it remained at < 1% through 6 mo. At pH 2.0 and 3.0, N-(2,6-dioxo-3-piperidinyl) acetamide was also detected. Pyroglutamic acid formed at pH ≤ 3.0. No degradation of NAQ was observed in a liquid nutritional product (pH = 6.5) after 3 mo.     

Blood pressure levels in diabetes mellitus

Levels of fasting plasma glucose, body mass index, serum total lipids, serum total cholesterol, serum triglycerides and blood pressure of 177 Libyan diabetic patients were determined. The respective mean values were 212.4 +/- 5.6 mg/dl, 26.6 +/- 0.45 kg/m2, 825.7 +/- 20.5 mg/dl, 176.4 mg/dl, 144 +/- 5.8 mg/dl and 135.3 +/- 1.7/83 +/- 0.89 mm Hg. The mean levels of all variables except plasma glucose are significantly higher in the female patients than their male counterparts. Correlations were present between blood pressure levels and age/body mass index/serum total lipids. There was a significant correlation between systolic pressure levels and the duration of diabetes. Serum cholesterol and serum triglyceride levels correlated with diastolic blood pressure levels only.     

Modulation detection interference in cochlear implant subjects

The aim of this study was to determine whether detection thresholds for amplitude modulated signals on a single electrode were influenced by a masking modulation on a second electrode in cochlear implant users. Data were collected from four post-linguistically deafened subjects using the Cochlear Limited prosthesis. Investigated were the effects of the spatial separation between test and masker electrodes, 0 to 5 electrodes (0 to 3.75 mm), and the amount of masking modulation: 24%, 48%, 72%, and 96% above detection thresholds. Initially, modulation detection thresholds for stimulation on a single electrode without masking modulation were obtained for a set of six electrodes in the middle of the array. Modulation detection thresholds on a fixed test electrode were then obtained with unmodulated and modulated masking on a second electrode, which was one of the six electrodes in the initial study. In both studies, thresholds were measured for modulated pulse duration at the modulation frequencies of 10-200 Hz. In the first study, the shape of the detection thresholds as a function of modulation frequency, the temporal modulation transfer function, generally resembled a low-pass filter for two subjects. For the other two subjects, the functions were relatively flat across modulation frequencies. In the second study, unmodulated masking resulted in a small elevation in detection thresholds across electrodes. Modulation detection interference (MDI), the difference between thresholds for the modulated maskers and the unmodulated masker, was greater for larger amounts of masking modulation than for smaller amounts of masking modulation. For three of the four subjects, MDI was higher for smaller spatial separations between the two electrodes than for larger spatial separations suggesting that a portion of MDI may be due to overlap of neural excitation distributions produced by stimulation on two electrodes in close proximity on the array.     

Contribution of an induction treatment in the surgical treatment of locally advanced non-small-cell cancers

From October 1988 to July 1990, 18 patients with marginally resectable non-small cell cancer (10 stage IIIa and 8 stage IIIb) were entered in a phase-II trial combining induction therapy with a subsequent thoracotomy. Induction therapy included 2 courses of chemotherapy (5-FU and cisplatinum) and radiotherapy (30 Gray in split course). Partial response was observed in 10 patients, and minimal response in 3. Thoracotomy disclosed unresectability in 3 patients. Fifteen complete resections consisted in 1 lobectomy and 14 pneumonectomies. There were no operative deaths (30 days). Postoperative recovery was uneventful in 3 patients with exploratory thoracotomy and in 1 patient with lobectomy. Following pneumonectomy, we observed 2 bronchopleural fistulae and 1 empyema. On pathology, 10 patients were stage IIIa, and 3 were stage I, whereas no residual tumor was found in 2 patients. During follow-up, local recurrence occurred in 2, and metastases in 8. On December 31st, 1993, 3 patients were alive at 44, 52, and 62 months respectively. Nine patients had died from cancer, and 3 from unrelated causes. Estimated survival was 66.7% at 1 year, 33.3% at 3 years, and 20% at 5 years. We conclude that induction therapy allowed satisfactory resection for marginally resectable tumors. Operative morbidity was increased in this group. However, the 5-year survival was similar to resectable stage IIIa cancer.