Doppler echocardiographic evaluation of prosthetic valves in tricuspid position

Doppler echocardiographic characteristics of 29 normally functioning prosthetic valves (23 mechanical, 6 biological) and 8 obstructed mechanical prostheses in the tricuspid position are reported. In normally functioning prostheses, peak velocity, mean pressure gradient, and pressure-half time were 1.25 +/- 0.18 m x sec(-1), 2.6 +/- 1.1 mm Hg, and 122.6 +/- 30.7 msec, respectively. Although no significant differences were seen in peak velocity and mean pressure gradient between mechanical and biological valves, the pressure half-time was significantly greater in biological valves. All normally functioning prostheses had a mean pressure gradient 5.5 mm Hg and pressure half-time < 200 msec. In obstructed bileaflet valves, peak velocity was 1.66 +/- 0.28 m x sec(-1), mean pressure gradient was 6.1 +/- 2.8 mm Hg, and pressure half-time was 265.8 +/- 171.7 msec. These Doppler data were significantly greater than those in normally functioning valves where the mean pressure gradient was 5.1 mm Hg and the pressure half-time was 156 msec in all except one patient. Pathological obstruction of a tricuspid prosthesis can be strongly suspected in patients with a mean pressure gradient > 5.5 mm Hg and a pressure half-time > 200 msec on Doppler echocardiography.     

Clinical and genetic determinants of urinary glucose excretion in patients with diabetes mellitus

Aims/IntroductionGlucosuria is a representative symptom in diabetes patients with poor glycemic control and in those treated with sodium–glucose cotransporter 2 inhibitors. Renal threshold levels of glucose excretion are known to vary among individuals, but factors contributing to glucosuria are not well characterized. The present study aimed to clarify clinical and genetic determinants of glucosuria in individuals with diabetes mellitus.Materials and MethodsThe 24‐h urinary glucose excretion was measured in 135 hospitalized patients on admission, with continuous measurement for five consecutive days in 75 patients. Genetic and clinical factors contributing to glucosuria were studied. As a genetic factor, SLC5A2 polymorphism was genotyped. A total of 476 participants (266 participants with type 2 diabetes and 210 healthy controls) were additionally genotyped for the association study of SLC5A2 with type 2 diabetes. A meta‐analysis was carried out with the present study and previous association studies.ResultsMultiple regression analysis showed that the independent variables of average blood glucose (β = 0.41, P = 1.4 × 10⁻⁷), estimated glomerular filtration rate (β = 0.28, P = 6.0 × 10⁻⁵), sex (β = 0.28, P = 5.7 × 10⁻⁵) and SLC5A2 rs9934336 polymorphism (β = 0.17, P = 0.02) were significantly correlated with urinary glucose excretion. The frequency of the A allele of rs9934336 tended to be lower in participants with type 2 diabetes than in controls (odds ratio 0.78, 95% confidence interval 0.53–1.13, not significant), and meta‐analysis showed a significant association between the A allele and type 2 diabetes (summary odds ratio for minor allele [A] 0.86, 95% confidence interval 0.78–0.94, P < 0.002).ConclusionsBlood glucose, estimated glomerular filtration rate, sex and SLC5A2 polymorphism were independent determinants of glucosuria in diabetes mellitus.     

β-Cell failure in diabetes: Common susceptibility and mechanisms shared between type 1 and type 2 diabetes

Diabetes mellitus is etiologically classified into type 1, type 2 and other types of diabetes. Despite distinct etiologies and pathogenesis of these subtypes, many studies have suggested the presence of shared susceptibilities and underlying mechanisms in β-cell failure among different types of diabetes. Understanding these susceptibilities and mechanisms can help in the development of therapeutic strategies regardless of the diabetes subtype. In this review, we discuss recent evidence indicating the shared genetic susceptibilities and common molecular mechanisms between type 1, type 2 and other types of diabetes, and highlight the future prospects as well.     

Comparative study of the natural history and operative outcome in patients 75 years and older with thoracic aortic aneurysm.

Surgery for thoracic aortic aneurysm (TAA) in patients 75 years and older is a high risk, but data for their natural history are not available. In the present study the subjects were 62 patients with TAA aged on average 78 years (range, 75-85 years) enrolled between August 1994 and December 2001: 20 operatively treated patients (OPE) and 42 medically managed patients (MED). All of them had been included in the indication for TAA surgery at the time of consultation. Hospital mortality rates and survival rates (Kaplan-Meier method) were compared among emergency OPE, elective OPE, and MED. There were 136 total patient-years of follow-up. Actuarial survival in MED (ie, the natural history) was 83% at 1 year after consultation and 41% at 3 years. Hospital mortality rates in emergency and elective OPE were 27% (3/11) and 0% (0/9), respectively (p=0.22), and the corresponding 3-year survival rates were 44% and 83% (p=0.019). Actuarial survival in elective OPE was higher than that in MED (p=0.022), but that of emergency OPE was similar to that for MED (p=0.17). Patients aged 75 years and older with TAA should undergo an elective operation if the aneurysm diameter is larger than 6 cm and if the patient is asymptomatic and in good anatomicosurgical, physical, and social condition.     

Prolonged hyperinsulinemia after subcutaneous injection of 2400 U regular insulin in a suicide attempt: Time course of serum insulin with frequent measurements

We studied the time course of serum insulin level in a patient who injected large amounts of regular insulin in an attempted suicide. A 58‐year‐old woman attempted suicide by subcutaneously injecting herself with 2400 U regular insulin. On arrival, the serum glucose level was 2.4 mmol/L (44 mg/dL) and the serum insulin level was 40,000 pmol/L (5700 μIU/mL). The serum insulin level was high, with a maximum of 110,000 pmol/L (16,000 μIU/mL) at 13 h after injection, followed by an initial rapid decrease and a subsequent slow decrease, with hyperinsulinemia lasting as long as 5 days after injection. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00211.x, 2012)