GooD4Mum: A general practice-based quality improvement collaborative for diabetes prevention in women with previous gestational diabetes.

AIMS: Gestational diabetes (GDM) and Type 2 diabetes pose tremendous health and economic burdens as worldwide incidence increases. Primary care-based systematic diabetes screening and prevention programs could be effective in women with previous GDM. GooD4Mum aimed to determine whether a Quality Improvement Collaborative (QIC) would improve postpartum diabetes screening and prevention planning in women with previous GDM in general practice. METHODS: Fifteen general practices within Victoria (Australia) participated in a 12-month QIC, consisting of baseline and four quarterly audits, guideline-led workshops and Plan-Do-Study-Act feedback cycles after each audit. The primary outcome measures were the proportion of women on local GDM registers completing a diabetes screening test and a diabetes prevention planning consultation within the previous 15 months. RESULTS: Diabetes screening increased with rates more than doubled from 26% to 61% and postpartum screening increased from 43%-60%. Diabetes prevention planning consultations did not show the same level of increase (0%-10%). The recording of body mass index improved overall (51%-69%) but the number of women with normal body mass index did not. CONCLUSIONS: GooD4Mum supported increased diabetes screening and the monitoring of high risk women with previous GDM in general practice.

Transfer of nitric oxide by blood from upstream to downstream resistance vessels causes microvascular dilation.

The discovery that hemoglobin, albumin, and glutathione carry and release nitric oxide (NO) may have consequences for movement of NO by blood within microvessels. We hypothesize that NO in plasma or bound to proteins likely survives to downstream locations. To confirm this hypothesis, there must be a finite NO concentration ([NO]) in arteriolar blood, and upstream resistance vessels must be able to increase the vessel wall [NO] of downstream arterioles. Arteriolar blood NO was measured with NO-sensitive microelectrodes, and vessel wall [NO] was consistently 25-40% higher than blood [NO]. Localized suppression of NO production in large arterioles over 500-1,000 microm with L-nitroarginine reduced the [NO] approximately 40%, indicating as much as 60% of the wall NO was from blood transfer. Flow in mesenteric arteries was elevated by occlusion of adjacent arteries to induce a flow-mediated increase in arterial NO production. Both arterial wall and downstream arteriolar [NO] increased and the arterioles dilated as the blood [NO] was increased. To study receptor-mediated NO generation, bradykinin was locally applied to upstream large arterioles and NO measured there and in downstream arterioles. At both sites, [NO] increased and both sets of vessels dilated. When isoproterenol was applied to the upstream vessels, they dilated, but neither the [NO] or diameter downstream arterioles increased. These observations indicate that NO can move in blood from upstream to downstream resistance vessels. This mechanism allows larger vessels that generate large [NO] to influence vascular tone in downstream vessels in response to both flow and receptor stimuli.

Lacustrine radiations in African Synodontis catfish.

Synodontis catfish are a species-rich, tropical pan-African genus that predominately occur in fluviatile environments, but which also form a small radiation within Lake Tanganyika (LT). Here we estimate Synodontis relationships, based on mitochondrial and nuclear DNA, greatly expanding previous sampling. Data were analysed using different methods of phylogenetic inference: Bayesian (also testing compositional heterogeneity), likelihood and parsimony, in order to investigate biogeographic history and the extent of intralacustrine speciation within this group. Bayesian-relaxed clock analyses were used to estimate timings of radiations. Our analyses reveal a single origin of the LT flock with the inclusion of the nonendemic S. victoriae, and that these taxa evolved relatively recently (5.5 Ma), considerably later than the formation of LT (9-12 Ma). Two internal endemic clades diversified at a similar time (2-2.5 Ma), corresponding to a period of climate change, when lake levels dropped. We find evidence for a further species flock, composed of riverine southern African taxa, the diversification of which is very rapid, 0.8 Ma (95% HPD: 0.4-1.5) and infer a similar scenario for the diversification of this flock to southern African serrachromine cichlids in that they radiated in the now extinct lake Makgadikgadi. We also reveal that the biogeographic history of Synodontis catfish is more complex than previously thought, with nonmonophyletic geographic species groupings.

Biological versus mechanical aortic valve replacement in children.

BACKGROUND: Aortic valve replacement in children remains challenging because of constraints imposed by available prosthetic devices. Potential risks of anticoagulation with mechanical valves and degeneration of other biological substitutes have kindled interest in the Ross procedure. This study outlines the evolution of our 27-year experience with prosthetic devices. METHODS: Ninety-nine patients who underwent aortic valve replacement (January 1973 through September 2000) were included in this study. Procedures included implantation of pulmonary autograft (PA) (n = 42), aortic homograft (AH) (n = 3), mechanical valves (MV) (n = 41), and xenograft tissue valves (XG) (n = 13). RESULTS: The mean follow-up times were: 3.8+/-1.3 years for PA, 3.5+/-1.5 years for AH, 7.7+/-4.7 years for MV, and 8.4+/-4.8 years for XG. There were no significant differences in perioperative outcomes among the groups (p < or = 0.05) or early deaths (2 each in the MV, AH, and PA groups). The incidence of valve-related complications and reoperations was high in the MV (n = 5), XG (n = 7), and AH (n = 1) groups as compared with the PA group (n = 3, p < 0.01). Early and late mortality for the series was 8.6% (n = 8). Overall, the reoperation rate was 20.7% (n = 18): 15.2% (5 of 33) MV, 70% (7 of 10) XG, 50% (1 of 2) AH, and 11.9% (5 of 42) for PA. The actuarial survival rate was 87.8% and 100% at 10 years for MV and XG, and 95.2% and 6.6% at 7 years for PA and AH. CONCLUSIONS: Aortic valve replacement in children can be performed with acceptable mortality and good long-term results. The Ross procedure, although more complicated, has the advantage of not requiring anticoagulation therapy, can be performed in all age groups, possesses inherent growth potential, and exhibits the most normal left ventricular outflow tract hemodynamics.

Clinical outcomes and indicators of normalization of left ventricular dimensions after Ross procedure in children.

Between 1993 and 2000, 50 patients (age range, 1 month to 18 years) who had left ventricular outflow tract (LVOT) disease and had undergone a Ross procedure were assessed using echocardiography. Aortic annulus size, valvular gradient, valve insufficiency, LV dimensions at end-systole and end-diastole, LV interventricular septal and posterior wall thickness, and LV mass index (LVMI) were measured. There was 1 early and 2 late deaths, and 5 reoperations. Aortic annulus size increased and degree of aortic insufficiency (AI) decreased, as did LV internal dimensions and LVMI. Peak pressure gradients declined from 73 +/- 18 mm Hg to 7 +/- 7 mm Hg, and LVMI regressed (167 +/- 6 g/m(2) v 108 +/- 6 g/m(2), P <.001) after 3 years. The degree of AI ranged from none to mild, and no patient has LVOT stenosis. Regression of LV dilatation and hypertrophy, good autograft valve function and durability, and a high survival rate suggest that the Ross procedure is preferred for most children who require aortic valve replacement.

High-spectral-resolution fluorescence light detection and ranging for mesospheric sodium temperature measurements.

The principle and practice of narrow-band light detection and ranging (lidar) for temperature measurements are discussed, with emphasis on a new two-frequency technique for measuring mesospheric Na temperature and density profiles. The uniqueness of this narrow-band lidar lies in the transmitter whose line-shape function can be measured directly. The frequency of the laser output can be monitored simultaneously during data acquisition with Doppler-free fluorescence spectroscopy by using a laboratory Na cell. These measurement techniques along with the procedures for data analysis are described in detail. At present the absolute temperature accuracy at the Na layer peak is +/-3 K (+/-4 K) with a vertical resolution of 1 km and an integration period of 5 min (2.5 min). Potential applications and furtherimprovements in this lidar technique are also discussed.

Apicoaortic valved conduits in a canine model.

Evaluating new developments in surgical methods and materials of aortic bypass prosthetics requires the use of an appropriate animal model, a well established surgical protocol and post surgical aortography. This article describes the surgical technique, post operative care and the angiographic technique used for an apicoaortic conduit placement in a canine model.

Pathogenesis of aneurysm formation opposite prosthetic patches used for coarctation repair. An experimental study.

Patch graft angioplasty for coarctation repair has been associated with late aneurysm formation opposite the prosthetic patch in some patients. Etiologic possibilities for this aneurysm formation include congenital abnormality of the aortic wall, surgical interruption of the vasa vasorum, intimal disruption because of extensive excision of the coarctation web, and rigidity of the prosthetic patch. To assess the effect of extensive intimal excision on the development of aneurysms, we operated on 12 dogs, performing a left thoracotomy and aortoplasty with Dacron (n = 6) or polytetrafluoroethylene patches (n = 6) and concomitant intimal excision opposite the patch. Ten control dogs underwent angioplasty with Dacron (n = 5) and polytetrafluoroethylene patches (n = 5) without excision of the intima. Serial aortograms of all animals showed aneurysm formation of the aorta opposite the patch in eight of the 12 dogs undergoing intimal excision. In contrast, no aneurysms developed in the control dogs (p less than 0.001). An additional five dogs underwent longitudinal aortotomy, intimal excision, and primary closure. Three dogs in this group demonstrated an aneurysm angiographically (p less than 0.02). Histologic analysis of the aneurysms and the control aortas revealed hyperplastic ingrowth of the intima over the denuded surface in the animals undergoing intimal excision. The elastic fibers in the media were intact and organized except in two aneurysmal specimens. We conclude that extensive resection of the intima with or without patch angioplasty predisposes aneurysm formation opposite the aortotomy and should be avoided during coarctation repair.

Externally stented polytetrafluoroethylene valved conduits for right heart reconstruction. An experimental comparison with Dacron valved conduits.

Valve-containing conduits have made possible the repair of many congenital anomalies that involve right ventricular-pulmonary arterial discontinuity. The distressing problem of neointimal peel formation with eventual conduit obstruction in patients with Dacron valved conduits has led to the need for premature replacement in many patients. Externally stented polytetrafluorethylene has demonstrated superior patency in the venous system experimentally and clinically and was believed to have potential advantages over Dacron for conduit construction. This study compares the transconduit resistance and the thickness of the neointimal peel in right ventricular-pulmonary arterial conduits constructed of externally stented polytetrafluoroethylene with those of woven Dacron. The 19 mm externally stented polytetrafluoroethylene conduits (Impra, Inc.) containing a Hancock porcine valve (Extracorporeal Inc.) were implanted in six adult mongrel dogs followed by proximal occlusion of the pulmonary artery. In six additional animals, a Dacron valved conduit of similar size and length was inserted. Cardiac output, transconduit gradient, and resistance were measured at operation and at 3 months. All conduits were subsequently explanted, opened longitudinally, and the thickness of the neointimal peel (excluding suture lines) measured. No hemodynamic differences were noted during the 3 month follow-up. However, the thickness of the neointimal peel was fourfold greater in Dacron conduits (609 +/- 144 mu) than in the conduits constructed of externally stented polytetrafluoroethylene (156 +/- 50 mu) (p less than 0.01). The thick peel in Dacron conduits extended into the outflow portion of the porcine valve cusps and prevented their full excision. The neointima in externally stented polytetrafluoroethylene conduits was thin and uniform and did not extend onto the leaflets or limit their mobility. This study demonstrated that the early hemodynamic performance of externally stented polytetrafluoroethylene conduits was comparable to that of Dacron conduits; Dacron conduits were subject to an accelerated rate of peel formation that affected leaflet mobility and may be a factor in early valve degeneration; a thin neointima formed in externally stented polytetrafluoroethylene conduits and valve leaflet motion was preserved. This study showed that externally stented polytetrafluoroethylene conduits offer advantages over Dacron valved conduits and warrant clinical application.