NMDA receptors mediate peripheral chemoreceptor afferent input in the conscious rat

N-methyl-D-aspartate (NMDA) glutamate receptors mediate critical components of cardiorespiratory control in anesthetized animals. The role of NMDA receptors in the ventilatory responses to peripheral and central chemoreceptor stimulation was investigated in conscious, freely behaving rats. Minute ventilation (VE) responses to 10% O2, 5% CO2, and increasing intravenous doses of sodium cyanide were measured in intact rats before and after intravenous administration of the NMDA receptor antagonist MK-801 (3 mg/kg). After MK-801, eupcapnic tidal volume (VT) decreased while frequency increased, resulting in a modest reduction in VE. Inspiratory time (TI) decreased, whereas expiratory time remained unchanged. The VE responses to hypercapnia were qualitatively similar in control and MK-801 conditions, with slight reductions in respiratory drive (VT/TI) after MK-801. In contrast, responses to hypoxia were markedly attenuated after MK-801 and were primarily due to reduced frequency changes, whereas VT was unaffected. Sodium cyanide doses associated with significant VE increases were 5 and 50 microg/kg before and after MK-801, respectively. Thus 1-log shift to the right of individual dose-response curves occurred with MK-801. Selective carotid body denervation reduced VE during hypoxia by 70%, and residual hypoxic ventilatory responses were abolished after MK-801. These findings suggest that, in conscious rats, carotid and other peripheral chemoreceptor-mediated hypoxic ventilatory responses are critically dependent on NMDA receptor activation and that NMDA receptor mechanisms are only modestly involved during hypercapnia.     

Disposition and fate of cucurbitacin B in five species of diabroticites

Five species of diabroticites with different host-plant preferences produced an essentially identical array of metabolites when fed radiolabeled cucurbitacin B synthesized in vivo and purified fromCucurbita maxima Duchesne seedlings. All species excreted the bulk of the cucurbitacin (67,17-94.59% total dpm), permanently sequestered a small proportion of a cucurbitacin conjugate in the hemolymph (0.98–2.76%), and apportioned the remainder between the gut, the body, and the eggs (when present). Markedly different ratios between the excretory metabolites (i.e., polar vs. unmetabolized cuc) suggest thatDibrotica virgifera virgifera, a grass specialist, andAcalymma vittatum, a cucurbit specialist, have lower rates of metabolic alteration than the polyphagousD. undecimpunctata howardi, D. balteata, andD. cristata, which is associated with relict prairies. Mean life-spans ofD. balteata and D. v. virgifera and maleA. vittatum decreased significantly with continuous feeding onCucurbita fruit containing cucurbitacins (vs. fruit devoid of cucs). The longevity of femaleA. vittatum, however, was unaffected by the presence of cucurbitacins.     

Evaluation of AMSR-E soil moisture results using the in-situ data over the Little River Experimental Watershed, Georgia

An operational global soil moisture data product is currently generated from the observations of the Advanced Microwave Scanning Radiometer (AMSR-E) aboard NASA's Aqua satellite using the retrieval procedure described in Njoku and Chan [Njoku, E.G. and Chan, S.K., 2006. Vegetation and surface roughness effects on AMSR-E land observations, remote sensing environment, 100(2), 190-199]. We have generated another soil moisture dataset from the same AMSR-E observed brightness temperature data using the Land Surface Microwave Emission Model (LSMEM) adopting a different estimation method. This paper focuses on a comparison study of soil moisture estimates from the above two methods. The soil moisture data from current AMSR-E product and LSMEM are compared with the in-situ measured soil moisture datasets over the Little River Experimental Watershed (LREW), Georgia, USA for the year 2003. The comparison study was carried out separately for the AMSR-E daytime and night time overpasses. The LSMEM method performed better than the current operational AMSR-E retrieval algorithm in this study. The differences between the AMSR-E and LSMEM results are mostly due to differences in various simplifications and assumptions made for variables in the radiative transfer equations and the soil and vegetation based physical models and the accuracy of the input surface temperature datasets for the LSMEM forward model approach. This study confirms that remote sensing data have the potential to provide useful hydrologic information, but the accuracy of the geophysical parameters could vary depending on the estimation methods. It cannot be concluded from this study whether the soil moisture estimation by the LSMEM approach will perform better in other geographic, climatic or topographic conditions. Nevertheless, this study sheds light on the effects of different approaches for the estimation of geophysical parameters, which may be useful for current and future satellite missions.     

Mechanical distraction for treatment of severe knee flexion contractures

Ten patients (14 knees) with severe knee flexion contractures were treated by gradual mechanical distraction using either the Ilizarov or Orthofix external fixator. Range of motion improved from an average flexion contracture of 60 degrees before surgery to 16 degrees at the follow-up evaluation. Range of motion results were graded good or excellent in five knees, fair in two knees, and poor in three knees. Average total arc of motion remained essentially unchanged when comparing the preoperative (59 degrees) with the follow-up results (63 degrees). However, the functional position of this arc improved significantly. Problems encountered included a "rebound" phenomena after frame removal, with loss of the temporarily increased total arc of motion. The role of hamstring tenotomy and radical posterior knee release remains unclear.     

Tenth anniversary of chapter Falcon's: notes for the history of the Venezuelan Association for the Advancement of Science (AsoVAC)]

Chapter Falcón of the Venezuelan Association for the Advancement of Science (AsoVAC) was chartered in 1984. In this essay we outline and analyze the circumstances and elements that made possible the establishment of this chapter. The key factors probably were a tight relation with Universidad Nacional Experimental Francisco de Miranda (UNEFM), which allowed to advance several common projects; the selection of realistic projects that could be "read" as organizational muscle; setting of goals that could be achieved with the resources at hand; and taking advantage of some of the psychological traits of Falcón State inhabitants. This chapter's future is pondered under the light of the unusual responsibilities that it will face during this year: mainly the organization of the AsoVAC annual convention, which will be held in Falcón for the first time.     

Three-year outcome after balloon aortic valvuloplasty. Insights into prognosis of valvular aortic stenosis

BACKGROUND: To identify predictors of long-term outcome after balloon aortic valvuloplasty, we analyzed data on 674 adults (mean age, 78 +/- 9 years; 56% were women) undergoing this procedure at 24 clinical centers who had a mean initial increase in aortic valve area of 0.3 cm2. METHODS AND RESULTS: Baseline data included clinical, echocardiographic, and catheterization variables. Follow-up data included mortality, cause of death, rehospitalization, 6-month echocardiography, and functional status. Kaplan-Meier curves and log-rank tests were used to evaluate survival in subgroups. Multivariate Cox regression models were used to identify independent predictors of survival. Overall survival was 55% at 1 year, 35% at 2 years, and 23% at 3 years, with the majority of deaths (70%) classified as cardiac by an independent review committee. Rehospitalization was common (64%), although 61% of survivors at 2 years reported improved symptoms. Echocardiography at 6 months (n = 115) showed restenosis from the postprocedural valve area of 0.78 +/- 0.31 cm2 to 0.65 +/- 0.25 cm2 (P < .0001). With stepwise multivariate analysis, sequentially adding clinical, echocardiographic, and catheterization variables, the overall model identified independent predictors of survival as baseline functional status, baseline cardiac output, renal function, cachexia, female gender, left ventricular systolic function, and mitral regurgitation. Baseline and postprocedural variables were examined to identify which subgroup of patients has the best outcome after aortic valvuloplasty. A "lower-risk" subgroup (28% of the study population), defined by normal left ventricular systolic function and mild clinical functional limitation, had a 3-year survival of 36% compared with 17% in the remainder of the study group. CONCLUSIONS: Long-term survival after balloon aortic valvuloplasty is poor with 1- and 3-year survival rates of 55% and 23%, respectively. Although survivors report fewer symptoms, early restenosis and recurrent hospitalization are common.     

The Benchmarking Effort for Networking Children's Hospitals (BENCHmark)

BACKGROUND: In 1992, 12 large children's hospitals established the Benchmarking Effort for Networking Children's Hospitals (BENCHmark). The goal was for the BENCHmark effort to supplement the hospitals' continuous quality improvement (CQI) programs and to speed adoption of best practices from peer institutions. For three years, the hospitals have been comparing data on cost, quality, and speed indicators. Also, "best practice" groups have met to share information on how processes can be improved. RESULTS: The BENCHmark hospitals have experienced significant process improvement in areas such as emergency department waiting time and admitting process time. EXAMPLE: The BENCHmark hospitals selected admitting as one of the first best practice groups to meet. Interdisciplinary staff from all BENCHmark hospitals met three times over the course of a year to define their indicator and share information on best practices. St Louis Children's Hospital, as a result, instituted a pre-arrival team and cross-trained staff, with the result being a reduction of admitting processing time from 58 minutes to 19 minutes. Same-day surgery patients now bypass the admitting department and go directly to the surgical floor. Patient and surgeon satisfaction has increased greatly. CONCLUSIONS: Hospitals that are planning to benchmark are encouraged to reach consensus on project goals and to focus on indicators that provide a clear business advantage. Physician involvement is key to improving performance and physicians will only be engaged if the hospitals against whom they are benchmarked are considered peers. Being willing to share initial data openly seems to be a key factor in determining successful integration of the BENCHmark process into hospital CQI efforts. The BENCHmark project has been so successful that a second group of 12 comparable pediatric institutions, known as the Network II, has been established.     

Duration of treatment with progesterone and regression of persistent ovarian follicles in cattle

The objective of the present study was to determine the duration of elevated concentrations of progesterone necessary to induce atresia of persistent ovarian follicles. Heifers were administered 25 mg of PGF2alpha on d 6 and 7 (d 0 = d of synchronized estrus) and a norgestomet implant from d 6 to 14. Ovaries were monitored by ultrasonography, and blood samples were collected on d 3, 5, 7, 9, 11, and 12 and daily from d 14 until ovulation. On d 12, heifers received either two progesterone-releasing intravaginal devices (PRID) for 6 h (6-h; n = 5), two PRID for 24 h (24-h; n = 5), or no treatment (CON; n = 5). Blood samples were collected at 15-min intervals from h -6 to 30 (PRID insertion = h 0) and analyzed for concentrations of LH. Characteristics of LH secretion were determined for consecutive 6-h periods (Period 0 to 5). Hourly blood samples, collected from h 0 to 29, were analyzed for concentrations of 17beta-estradiol (estradiol) and progesterone. The dominant ovarian follicles present on d 7 increased in size to 15.4+/-.3 mm on d 12 ("persistent follicle"). Following removal of the PRID and norgestomet implants, atresia of persistent follicles and ovulation of new follicles were induced in one of five and in four of five heifers in the 6-h and 24-h treatments, respectively. Persistent follicles ovulated after withdrawal of norgestomet in all other heifers. Concentrations of progesterone were increased from h 1 to 7 in the 6-h and h 1 to 26 in the 24-h treatment. Frequency of LH pulses was reduced (P < .05) during Periods 1 to 2 in the 6-h and Periods 1 to 5 in the 24-h treatment relative to the CON treatment. By h 10, concentrations of estradiol in the 6-h and 24-h treatments were lower (P < . 05) than in the CON treatment. This suppression continued through h 29 in the 24-h treatment (P < .05), whereas concentrations in the 6-h treatment were intermediate to those of the CON and 24-h treatments after h 14. Suppression of pulsatile LH release and estradiol secretion was evident with 6 and 24 h of treatment with progesterone, but only the 24-h treatment induced atresia of persistent follicles in a majority of the heifers.     

An approach to integrating intelligentdiagnostics and supervision of machine tools

Arguments are presented for the necessity of integrating diagnostics and supervision in technological machines. An example of integrated diagnostics and supervision of the machine tool main drive, based on an expert system and neural network, is shown. Problems of intelligent thermal displacement supervision and questions related to practical supervision of machining centres are presented.