Differential protein expression during aging in ventricular myocardium of Fischer 344 x Brown Norway hybrid rats.

The aging heart undergoes well characterized structural changes associated with functional decline, though the underlying mechanisms are not understood. The aim of this study was to determine to what extent ventricular myocardial protein expression was altered with age and which proteins underwent protein nitration. Fischer 344 x Brown Norway F1 hybrid (FBN) rats of four age groups were used, 4, 12, 24, and 34 months. Differential protein expression was determined by 2-DE and proteins were identified by peptide mass fingerprinting. Altered protein nitration with age was assessed by immunoblotting. Over 1000 protein spots per sample were detected, and 255 were found to be differentially expressed when all aged groups were compared to young rats (4 months) (p0.05). A strong positive correlation between differential protein expression and increasing age (p=0.03, R(2)=0.997) indicated a progressive, rather than abrupt, change with age. Of 46 differentially expressed proteins identified, seventeen have roles in apoptosis, ten in hypertrophy, seven in fibrosis, and three in diastolic dysfunction, aging-associated processes previously reported in both human and FBN rat heart. Protein expression alterations detected here could have beneficial effects on cardiac function; thus, our data indicate a largely adaptive change in protein expression during aging. In contrast, differential protein nitration increased abruptly, rather than progressively, at 24 months of age. Altogether, the results suggest that differential myocardial protein expression occurs in a progressive manner during aging, and that a proteomic-based approach is an effective method for the identification of potential therapeutic targets to mitigate aging-related myocardial dysfunction.

Analgesic efficacy and side effects of subarachnoid sufentanil-bupivacaine administered to women in advanced labor.

BACKGROUND AND OBJECTIVES: Previous studies of labor analgesia using subarachnoid sufentanil (alone or with adjuvants) have focused on women in the early first stage of labor. This study prospectively evaluated analgesia and side effects of subarachnoid sufentanil (10 micrograms) plus bupivacaine (2.5 mg) in parturients with cervical dilation of 7 cm or more. METHODS: In an open-label, nonrandomized trial, 32 parturients in the late first stage of labor, who had requested regional anesthesia, consented to subarachnoid injection of sufentanil (10 micrograms) and bupivacaine (2.5 mg). Patients rated their pain by a verbal pain score (0-10 scale) prior to regional anesthesia, 5 minutes after subarachnoid injection, and every 20 minutes thereafter until delivery or request for additional analgesia. Blood pressure, pruritus, Bromage motor block score (0-3), mode of delivery, and need for supplemental analgesics were recorded. RESULTS: Lumbar puncture was successful in 30 women. Pain scores (mean +/- SD) were 8.7 +/- 1.0 prespinal and 0.7 +/- 1.5 5 minutes postinjection, and remained less than 5 for 130 minutes after the spinal injection. Of these 30 patients, 24 had unassisted vaginal delivery, 4 had instrumental vaginal delivery (3 vacuum, 1 low forceps), and 2 had cesarean delivery. Of the 28 patients who delivered vaginally, 19 did not require supplemental analgesics and had a delivery pain score of 5 or lower. Blood pressure decreased after spinal analgesia (P < .05), and necessitated treatment in three patients. The Bromage motor block score was 0 in 26 patients and 1 in 4 patients. Pruritus was noted by 22 patients. CONCLUSION: In parturients with cervical dilation of 7 cm or more, subarachnoid sufentanil-bupivacaine produces rapid analgesia with an effective duration of approximately 130 minutes.

Annular (HSURIA) resonators: some experimental studies including polarization effects.

A repetitively pulsed CO(2) laser facility was developed for testing annular resonators. The large-aperture device exhibits generally uniform gain over an annular region of 18-cm o.d. and 10-cm i.d. The half-symmetric unstable resonator with internal axicon (HSURIA) was tested at equivalent Fresnel numbers up to 4.5. This resonator design incorporates a W-axicon mirror beam compactor that transforms a cylindricalmode region into an annular-mode region. Two HSURIA configurations were evaluated: (a) with a conical end mirror and (b) with a flat end mirror in the annular leg. With the conical end mirror, the aligned resonator produced a predominantly higher-order azimuthal mode with an on-axis null in the far field. The output was strongly linearly polarized with the electric-field vector tangential to the optic axis in both the near and far fields. The higher-order tangentially polarized mode appears to be the result of a geometric polarization scrambling effect caused by the conical end mirror. The boundary conitions for the conical or W-axicon mirrors imply that the radial electric field has a 180 degrees phase shift on reflection, whereas the tangential component is unchanged. Thus, a tangentially polarized mode is self-reproducing, but a linearly polarized mode is not. To eliminate the polarization scrambling effect in the HSURIA, the conical end mirror was replaced with a flat end mirror. The HSURIA with a flat end mirror produced a central spot in the far field that indicated an l = 0 mode with no spatial variations in polarization. Beam quality was measured in terms of the ratio n(2) of the theoretical (geometric-mode) power transmitted through an aperture of the central lobe diameter to the observed power; n(2) values as low as 1.2 were obtained. The variation of beam quality with tilt of the flat end mirror indicated a factor of 2 degradation in n(2) for a 20-microrad tilt, which is in good agreement with theory.

Annular converging wave cavity.

A new type of resonator that generates an annular geometric mode by use of spherical mirrors has been developed. The four-element cavity consists of an external confocal unstable resonator with a double-sided 45 degrees coupling mirror and a flat feedback mirror. The flat feedback mirror is placed on the plane wave side of the confocal cavity to form an annular mode between the feedback mirror and the coupling mirror. A plane annular wave (matched to an annular gain medium) is fed back into the unstable resonator that alternately converges and diverges to produce a diverging annular output beam. Experiments were performed on a cw HF laser. Observations of mode patterns on the flat feedback mirror and the convex mirror and of far-field beam quality were made. Far-field measurements indicated near-diffraction-limited beam quality for a peak on-axis intensity mode on the convex mirror. A nearly uniform annular mode was observed on the flat feedback mirror.

Variable-aperture calorimeter for an unstable resonator.

A new technique for measuring the output power from a cw edge-coupled unstable resonator has been developed and applied to a cw DF laser. An internal-cavity calorimeter was used that permits measurement of output power with a variable rectangular mode geometry while containing the radiation inside the resonator. The variable aperture calorimeter absorbing scraper (VACAS) device consists of an absorbing copper plate calorimeter assembly, which replaces the 45 degrees output coupling mirror of a conventional edge-coupled unstable cavity. A rectangular hole in the plate of variable width w and height h defines a rectangular mode of variable width Mw and height Mh within the geometric optics approximation, where M is the magnification. Two important applications of VACAS are (1) the determination of the optimum mode geometry for a cw diffusion-type chemical laser where there is significant variation in gain across the unstable resonator mode and (2) the determination of the power tradeoff between mode width and the number of folds in a folded unstable resonator configuration.