Insulin secretory function in Type 2 diabetes: Does it matter how you measure it?

The following estimates of insulin secretory function have been used widely to evaluate the role of pancreatic β-cells in the pathogenesis and treatment of patients with type 2 diabetes (2DM): (i) Homeostatic Model Assessment (HOMA)-β, a calculation based on fasting plasma glucose and insulin concentrations; (ii) post-glucose acute insulin response (AIRg), the increment in insulin concentration measured in the 5 min after intravenous glucose; and (iii) ΔI/ΔG, the ratio of the increment in plasma insulin concentration (I)/increment in plasma glucose concentration (G) 30 min after the oral administration of 75 g glucose. Experiments based on these approaches have led to a widely held point of view that that the natural history of 2DM is characterized by a progressive increase in the magnitude of hyperglycemia, secondary to an inexorable decline in pancreatic β-cell function: the greater the increase in plasma glucose concentration, the greater the impairment of the ability of the pancreas to secrete insulin. In the present review, theoretical questions are raised as to the physiological validity of these estimates of insulin secretory function and experimental data are presented demonstrating that hourly measurements of plasma insulin and glucose concentrations in response to mixed meals throughout an 8-h day lead to a very different point of view. Studies are also reviewed that question the 'inexorability' of the changes in insulin secretory function that have been reported. It is concluded that it may be time to challenge current conventional wisdom as to the role of the β-cell in the natural history of 2DM.     

What is the white-coat effect and how should it be measured?

The white coat effect is conceived as a measure of the blood pressure response to a clinic visit, but there is no agreement as to exactly how it should be defined. The most widely used definition is the difference between the average clinic and daytime ambulatory blood pressures, but other methods that have been used include the difference between clinic and home pressures, measurements using ambulatory blood pressures only, clinic measurements only, and laboratory (reactivity) testing. Few studies have compared the different methods, but the reactivity method has reported bigger changes of blood pressure and heart rate than the others. The effect tends to be greater in older than younger patients, in women than in men, but is present to a greater or lesser degree in almost all hypertensive patients. It is diminished but not obliterated by drug treatment. It is not closely related to overall blood pressure variability, and does not predict cardiovascular risk. The white coat effect appears to be idiosyncratic to the clinic setting.     

What is the effect of combining artesunate and praziquantel in the treatment of Schistosoma mansoni infections?

A group of 110 individuals with Schistosoma mansoni infection was investigated. Patients were allocated to one of three treatment groups and given artesunate or praziquantel alone or both in combination. Combined artesunate-praziquantel significantly increased the number of individuals cured at 5 weeks post-treatment, but at 12 weeks was only better than artesunate alone and at 24 weeks there was no statistically significant difference between the three groups. Egg count reduction rate was similar to the rate obtained with praziquantel used alone.     

Acupuncture: is it effective for treatment of insulin resistance?

Insulin resistance (IR) is closely associated with obesity, type 2 diabetes mellitus (T2DM), hypertension, polycystic ovary syndrome (PCOS), non‐alcohol fatty liver diseases (NAFLD) and metabolic syndrome and is also a risk factor for serious diseases such as cardiovascular diseases. Pharmacological treatments available for IR are limited by drug adverse effects. Because acupuncture has been practiced for thousands of years in China, it has been increasingly used worldwide for IR‐related diseases. This review analyses 234 English publications listed on the PubMed database between 1979 and 2009 on the effectiveness of acupuncture as a treatment for IR. These publications provide clinical evidence, although limited, in support of the effectiveness of acupuncture in IR. At this stage, well‐designed, evidence‐based clinical randomized controlled trial studies are therefore needed to confirm the effects of acupuncture on IR. Numerous experimental studies have demonstrated that acupuncture can correct various metabolic disorders such as hyperglycemia, overweight, hyperphagia, hyperlipidemia, inflammation, altered activity of the sympathetic nervous system and insulin signal defect, all of which contribute to the development of IR. In addition, acupuncture has the potential to improve insulin sensitivity. The evidence has revealed the mechanisms responsible for the beneficial effects of acupuncture, though further investigations are warranted.     

What is the upper limit of normal for the common bile duct on ultrasound: how much do you want it to be?

Conventionally, the upper limit of normal for the common bile duct as measured by ultrasound is considered to be 6 mm. This review is a somewhat personalized account of how that number became the convention and cautions the reader to avoid being slavish in the use of this number. Two specific cautions are not to apply this limit to older patients and to consider where in the common bile duct the measurement was taken, as measurements taken closer to the pancreas may be larger than ones closer to the liver.     

What is new in the treatment of perianal fistulae in Crohn's disease?

Perianal fistulae in Crohn's disease occur frequently and are the most difficult perianal manifestation of the disease to treat. The relation between the fistula and the sphincter apparatus and pelvic floor forms the basis for the surgical problems. Simple lower fistulae with regard to the anal sphincters can be treated as any other perianal fistula with a technique in which the fistulous tract is layed open with only a minor division of sphincter muscle. Complex high-situated fistulae require another treatment approach in order not to render the patient incontinent. Therefore, it is of prime importance to be informed about the nature of the fistula before operation. Magnetic resonance imaging seems to give all the information needed on complex fistulae that was not available previously. It allows a thorough surgical planning of the procedure in which all the fistulous tissue is removed with primary repair of the pelvic floor and sphincters if necessary. Our first results are promising.