Maturity onset diabetes of the young: Seek and you will find.

Maturity onset diabetes of the young (MODY) is a monogenic, autosomal dominant form of diabetes characterised by mutations in genes resulting in dysfunction of pancreatic ß-cells and subsequent insulin production. We present a family with HNF1A-MODY due to a likely pathogenic mutation in HNF1A (c.59G>A, p.Gly20Glu), diagnosed a long time after the first diagnosis of diabetes. Currently 13 MODY subtypes caused by mutations in 13 genes, are known. We describe the four most prevalent forms in more detail, i.e. HNF4A-MODY, GCK-MODY, HNF1A-MODY and HNF1B-MODY, together responsible for probably 99% of MODY cases. The different forms of MODY vary in prevalence, severity of diabetes, occurrence and severity of diabetic complications and response to treatment. New tools, such as the MODY probability calculator, may be of assistance in finding those patients in whom further genetic testing for possible MODY is warranted. However, as our described family shows, a doctor's clinical eye and taking the time for a detailed family history may be equal to, or even better than, the best prediction rule.

Long-term blood pressure monitoring and echocardiographic findings in patients with end-stage renal disease: reverse epidemiology explained?

BACKGROUND: In patients with end-stage renal disease (ESRD) hypertension is common and often leads to left ventricular (LV) hypertrophy and diastolic dysfunction, but hypotension at the onset of dialysis is associated with increased mortality. We studied blood pressure data over longer periods of time in patients on haemodialysis and related them to echocardiographic outcome, in order to elucidate these contradictory findings. METHODS: In 50 haemodialysis patients mean arterial pressure (MAP) and pulse pressure (PP) were calculated in the first three months of haemodialysis, the complete period from the start of haemodialysis until echocardiography and the last three months of haemodialysis before echocardiography. Hypertension load, pulse pressure and interdialytic weight gain were quantified and related to echocardiography. RESULTS: LV mass index was associated with MAP in all three periods, and also with the hypertension load, PP and PP load. In patients with LV dilatation, MAP and PP averaged over the complete period of dialysis were 5 to 7 mmHg higher than in patients without LV dilatation. Blood pressure parameters were the same in patients with or without LV diastolic dysfunction or systolic dysfunction. Systolic dysfunction was more frequent in patients undergoing long-term haemodialysis treatment. Interdialytic weight gain was not associated with any of the echocardiographic variables. CONCLUSION: When long-term blood pressure values are considered, hypertension is associated with parameters of early cardiac damage such as increased LV mass index and not with parameters of advanced heart failure such as systolic dysfunction. This supports the hypothesis that the presence of advanced heart failure reciprocally influences blood pressure in a negative way, thereby explaining the 'reverse epidemiology' of blood pressure and mortality in ESRD.

Overhauser instrumentation: similarities with and differences from MRI.

The main subject of this paper is a comparison of the instrumentation of the Overhauser imager (OI) and the MRI scanner. After introducing the OI system architecture we concentrate on different chains of the OI scanner hardware system. For each chain an overview of the typical requirements, designs and specifications of chain components is given. We compare each OI chain with the corresponding MRI chain and draw conclusions about what makes OI design easier and what are the typical OI problems. In the final conclusion we summarize the main benefits and the main drawbacks of the OI.

Low-frequency quadrature mode birdcage resonator.

The birdcage resonator is frequently used in conventional MRI because of its excellent attributes. Its use in low-field MRI is restricted to field strengths higher than, for example, 0.1 T, dependent on the size of the coil. This is because of the intrinsically low inductance value of the birdcage coils. Furthermore, the sensitivity of the birdcage at low field strengths is significantly lower when compared to, for example, the solenoid. Both problems can be overcome with the multiturn technique and a novel wound birdcage coil. The quadrature mode wound birdcage coil presented in this paper can be used at frequencies as low as 100 kHz. Its sensitivity is also increased when compared to the conventional strip-ring birdcage. Homogeneity, effective volume, and methods to increase the resonator bandwidth to match the signal bandwidth are left intact. The latter is a typical low-field problem.

Transverse low-field RF coils in MRI.

Imaging at low fields imposes a number of nonstandard requirements on the RF coil. At low fields, coil losses are dominant over patient losses. This means that even more stress is put on the quality factor Q. Furthermore, the low frequency also implies a high inductance L and/or a high capacitance C product. Just increasing the capacitance C results in a difficult optimal matching to the preamplifier as well as increased costs and higher complexity of the resonator construction. Coils with a high quality factor Q and a high inductance are thus required at low fields. Birdcage coils possess a number of advantages over saddle and solenoidal coils. However, the currently used birdcages have inherently low inductances limited by the size of the coil. The problem can be solved by a novel design in which the strip configuration for inductors is abandoned and the inductors are realized as a certain number of turns. The Q factor can be further improved by using Litz wire. Three novel transverse RF coils with high inductances are presented and compared with each other as well as to the standard coils. Both linear and quadrature modes are discussed.