Steroid glaucoma: corticosteroid-induced ocular hypertension in cats.

This study was undertaken to develop a feline model of corticosteroid-induced ocular hypertension. In the first experiment, eight cats were selected whose intraocular pressure (17 +/- 0.4 mmHg) was consistently below the mean baseline intraocular pressure of our colony (24 +/- 0.5) during the preceding 2 months. Unilateral twice or thrice daily topical application of 10 microliters 1% dexamethasone sodium phosphate caused a gradual intraocular pressure increase that became significant (P less than 0.05) within 2-3 weeks. There was no significant change in body weight, but several eyes developed cataracts. Similar results were obtained with treatment of normotensive cat eyes with dexamethasone, or with 1.0% prednisolone acetate (PredForte) twice a day. Topical application of PGF2 alpha-1-isopropyl ester (0.1 or 0.25 microgram PG equivalent) to such steroid-treated eyes yielded significant intraocular pressure reduction and pupillary miosis, similar in magnitude to those exhibited by normal eyes. When dexamethasone treatment was reduced to once daily, after prolonged twice daily treatment, intraocular pressure decreased only slightly within 10 days. When dexamethasone treatment was stopped, intraocular pressure declined to normal levels within 6-7 days. These findings show that adult cat eyes develop steroid-induced ocular hypertension that is maintained and reversible. As opposed to previous findings on rabbits, steroid-induced feline ocular hypertension appears to be a good model for this clinical condition and may be suitable for the testing of potential glaucoma drugs.     

The B-cell development independent of the bursa of Fabricius but dependent upon the thymus in chickens treated with testosterone propionate.

Spleen cells taken from chickens treated with testosterone propionate, surgically bursectomized and immunized, were treated with anti-bursa-cell antiserum in the presence of complement, and transferred together with the mixed antigens into immunodeficient chickens. The recipient chickens showed restored capacity for antibody response to sheep red blood cells. In contrast, adoptive immune responses by spleen cells from normal chickens were abolished by treating with anti-bursa-cell antiserum in the presence of complement. These findings indicate that antibody-forming cells in TP-treated chickens do not bear cell-surface antigens specific for bursa cells; Testosterone-treated chickens were thymectomized at 7 days of age and immunized with the mixed antigens; the chickens thus treated were not able to produce antibodies. Thymocytes and thymus-derived cells taken from normal chickens were transferred into the testosterone-treated and surgically thymectomized chickens; but the antibody responses were not restored, indicating that absence of antibody formation in testosterone-treated, thymectomized birds is not due to lack of T cells as such. This result was confirmed by using adoptive transfer of B cells taken from testosterone-treated chickens together with T cells.     

Evaluation of the PhysioFlex closed-circuit anaesthesia machine

The concentrations of nitrous oxide, sevoflurane and oxygen in the circle system of a closed-circuit anaesthesia machine, the PhysioFlex, were measured in seven patients. During anaesthesia, the settings for each gas were changed and their concentrations recorded. At the induction of anaesthesia, it took 80-510s (median 190s) for the end-tidal sevoflurane concentration to reach 2.0%, and 920-2640s (median 1500s) for the oxygen in the breathing circuit to reach 30%. At this time, the nitrous oxide concentration was 60+/-3% (mean+/-SD). During anaesthesia, it took 90-480s (median 140s) for the end-tidal sevoflurane concentration setting to decrease from 3.0 to 1.0%, and 90-400s (median 110s) to return from 1.0 to 3.0%. When the inspired oxygen was increased from 30 to 50%, circuit concentrations reached equilibrium in 40-60s (median 40s), and when decreased from 50% back to 30%, equilibrium took 310-470s (median 450s). During recovery from anaesthesia, inspiratory sevoflurane concentration took 40-70s (median 50s) to decrease to 0.2%. The PhysioFlex provided adequate control of sevoflurane and oxygen concentrations, but not of increasing nitrous oxide concentrations.     

Streptococcus thermophilus extends lifespan through activation of DAF-16-mediated antioxidant pathway in Caenorhabditis elegans

Streptococcus thermophilus bacteria, which are widely used as fermented starter for dairy production, exert various beneficial health effects. Nevertheless, even though pro-longevity effects of various probiotics have been reported, no report has described Streptococcus thermophilus effects on longevity. This study was conducted to evaluate Streptococcus thermophilus effects on lifespan extension and to elucidate the Streptococcus thermophilus-mediated longevity mechanism using Caenorhabditis elegans worms as a model animal. They were fed standard food (Escherichia coli OP50) or Streptococcus thermophilus from the young adult stage. Feeding with Streptococcus thermophilus, compared to Escherichia coli OP50, to Caenorhabditis elegans extend the lifespan, reduced lipofuscin accumulation, and maintain vigorous locomotion. Feeding with Streptococcus thermophilus did not alter the worm growth curve or the offspring number, indicating that the Streptococcus thermophilus-mediated lifespan extension is not attributable to caloric restriction. The qRT-PCR data showed that Streptococcus thermophilus increased the expression of daf-16 and some of its downstream antioxidant genes. Furthermore, the pro-longevity effects of Streptococcus thermophilus were decreased in loss-of-function mutant of daf-16. Results show that Streptococcus thermophilus extends the lifespan of Caenorhabditis elegans through DAF-16-mediated antioxidant pathway activation.     

Exposure of the mitral valve using flexible self-retaining retractors and an atrial hook

We hereby present our technique for using the self-retaining flexible arm retractor and its attachments for mitral valve exposure. The Aortic Valve Assistant, which was developed for aortic valve exposure, is also very useful for exposure of the inferior wall of the left atrium. Our modified atrial hook provides excellent exposure of the anterior mitral annulus. Extensive dissection and the combined use of the flexible arm and attachments allows us comfortable access for mitral valve operations.     

Adding coronary artery bypass grafting to aortic valve replacement increases operative mortality for elderly (70 years and older) patients with aortic stenosis

Objective

This retrospective study aimed to determine the effect of simultaneous aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) on operative outcomes and long-term survival in elderly patients with a high prevalence of comorbidity.

Methods

One hundred and fifty-seven elderly patients (70 years old or older) undergoing isolated AVR (n = 120) or combined AVR/CABG (n = 37) were evaluated. Operative outcomes were compared between the two surgical groups. Long-term survival was also compared between the groups using the Kaplan–Meier method and long-rank (Mantel–Cox) test.

Results

Operative mortality was 0.8 % for the isolated AVR group and 5.4 % for the combined AVR/CABG group (p = 0.076). The length of the intensive care unit stay for the combined AVR/CABG group was significantly longer than that for the isolated AVR group (median: 40 vs. 21 h, p = 0.008). However, the occurrence rate of hospital complications, such as reoperation for bleeding, deep sternal infection, supra-ventricular arrhythmia, and neurological complications, was similar between the two groups. Actuarial survival at 3 and 5 years was 82.3 and 80.9 % for the isolated AVR group, and 88.3 and 73.0 % for the combined AVR/CABG group, respectively (p = 0.637).

Conclusions

The satisfactory operative and long-term results in our study support a more aggressive simultaneous coronary revascularization combined with AVR for aortic valve stenosis in elderly patients.     

Multiple spatiotemporal modes of actin reorganization by NMDA receptors and voltage-gated Ca2+ channels

Cytoskeleton is believed to contribute to activity-dependent processes underlying neuronal plasticity, such as regulations of cellular morphology and localization of signaling proteins. However, how neuronal activity controls actin cytoskeleton remains obscure. Taking advantage of confocal imaging of enhanced GFP-actin in the primary culture of hippocampal neurons, we show that synaptic activity induces multiple types of actin reorganization, both at the spines and at the somatic periphery. Activation of N-methyl-d-aspartate receptors, accompanied with a local rise in [Ca(2+)]i, was sufficient to trigger a slow and sustained recruitment of actin into dendritic spines. In contrast, opening of voltage-gated Ca(2+) channels rapidly and reversibly enhanced cortical actin at the somatic periphery but not in the spines, in keeping with a high transient rise in somatic [Ca(2+)]i. These data suggest that spatiotemporal dynamics of [Ca(2+)]i, triggered by activation of N-methyl-d-aspartate receptors and voltage-gated Ca(2+) channels, provides the molecular basis for activity-dependent actin remodeling.     

Quantification of the degradation products of sevoflurane using four brands of CO2 absorbent in a standard anesthetic circuit

Purpose. CO₂ absorbents convert sevoflurane to fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (compound A), whose toxicity in rats raises concern regarding the safety of sevoflurane in a low-flow system. The type of CO₂ absorbent is one of factors that affect compound A concentration in the anesthetic circuit. The aim of the present study was to investigate the concentration of compound A in an anesthetic model circuit following the use of different brands of soda lime and Baralyme. Methods. We measured the concentrations of compound A in four different brands of CO₂ absorbent using a low-flow (1 l·min⁻¹ fresh gas) model circuit in which 2% sevoflurane was circulated. Sodasorb II, Baralyme, Sofnolime and Wakolime-A were used as CO₂ absorbents. The concentration of compound A was measured hourly, and the temperature of the CO₂ absorbent was monitored. Results. The maximum concentration of compound A in the circuit was highest for Baralyme (25.5 ± 0.6 ppm) (mean ± SD), followed by Sodasorb II (18.9 ± 1.6 ppm), Wakolime-A (16.1 ± 0.7 ppm), and Sofnolime (15.8 ± 1.4 ppm). The maximum temperature was 50.8 ± 1.3°C for Baralyme, 48.8 ± 1.3°C for Wakolime-A, 47.0 ± 1.4°C for Sodasorb II, and 43.5 ± 3.9°C for Sofnolime. Conclusion. The relative concentrations of compound A in the low-flow circuit were Baralyme > Sodasorb II > Wakolime-A = Sofnolime. Received: August 27, 1999 / Accepted: January 13, 2000     

New subjects for exceeding conventional on-pump CABG

Coronary artery bypass grafting (CABG) used to be performed under cardiac arrest and cardiopulmonary bypass (CPB). During the last decade, efforts were made to minimize CPB-related complications. The technique of off-pump CABG (OPCAB) has been established during the last 5 years. Elimination of CPB and OPCAB has successfully reduced a number of perioperative complications and has provided early patient recovery. A compression type of coronary stabilizer was used early phase of OPCAB. Off-pump revascularization using the compression device was limited to the anterior wall of the heart. Bypass to the posterior wall under a beating heart was not popular until the suction type of stabilizer had become available. A suction device assisted by the Lima's pericardial suture allowed us to perform bypass grafting any aspects of the heart. Recently, we are skeltonizing the arterial grafts using the Harmonic scalpel. Applying skeltonizing technique to the radial artery or internal thoracic artery, we can successfully perform sequential grafting in selected cases. The number of distal anastomoses has been gradually increased as the device and technique were advanced (2.1 distal anastomoses with a compression device, 2.9 with a suction device, and 3.2 with the skeltonization technique). The frequency of the complete revascularization also increased. On the other hand, the complications associated with the procedure were comparable among these three off-pump methods, but were significantly fewer than on-pump CABG. Currently performed OPCAB can provide almost same number of distal anastomoses as on-pump CABG, with less frequency of postoperative mortality and morbidity, and with early patient recovery. These favorable results were attributed to the progress of the device and technique.