Kristin Persson

PAC1 receptor–deficient mice display impaired insulinotropic response to glucose and reduced glucose tolerance

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a ubiquitous neuropeptide of the vasoactive intestinal peptide (VIP) family that potentiates glucose-stimulated insulin secretion. Pancreatic beta cells express two PACAP receptor subtypes, a PACAP-preferring (PAC1) and a VIP-shared (VPAC2) receptor. We have applied a gene targeting approach to create a mouse lacking the PAC1 receptor (PAC1(-/-)). These mice were viable and normoglycemic, but exhibited a slight feeding hyperinsulinemia. In vitro, in the isolated perfused pancreas, the insulin secretory response to PACAP was reduced by 50% in PAC1(-/-) mice, whereas the response to VIP was unaffected. In vivo, the insulinotropic action of PACAP was also acutely reduced, and the peptide induced impairment of glucose tolerance after an intravenous glucose injection. This demonstrates that PAC1 receptor is involved in the insulinotropic action of the peptide. Moreover, PAC1(-/-) mice exhibited reduced glucose-stimulated insulin secretion in vitro and in vivo, showing that the PAC1 receptor is required to maintain normal insulin secretory responsiveness to glucose. The defective insulinotropic action of glucose was associated with marked glucose intolerance after both intravenous and gastric glucose administration. Thus, these results are consistent with a physiological role for the PAC1 receptor in glucose homeostasis, notably during food intake.

Barriers to adherence to hypertension guidelines among GPs in southern Sweden: A survey.

Objective. To evaluate barriers to adherence to hypertension guidelines among publicly employed general practitioners (GPs). Design. Questionnaire-based survey distributed to GPs in 24 randomly selected primary care centres in the Region of Skåne in southern Sweden. Subjects. A total of 109 GPs received a self-administered questionnaire and 90 of them responded. Main outcome measures. Use of risk assessment programmes. Reasons to postpone or abstain from pharmacological treatment for the management of hypertension. Results. Reported managing of high blood pressure (BP) varied. In all, 53% (95% CI 42–64%) of the GPs used risk assessment programmes and nine out of 10 acknowledged blood pressure target levels. Only one in 10 did not inform the patients about these levels. The range for immediate initiating pharmacological treatment was a systolic BP 140–220 (median 170) mmHg and diastolic BP 90–110 (median 100) mmHg. One-third (32%; 95% CI 22–42%) of the GPs postponed or abstained from pharmacological treatment of hypertension due to a patients advanced age. No statistically significant associations were observed between GPs’ gender, professional experience (i.e. in terms of specialist family medicine and by number of years in practice), and specific reasons to postpone or abstain from pharmacological treatment of hypertension. Conclusion. These data suggest that GPs accept higher blood pressure levels than recommended in clinical guidelines. Old age of the patient seems to be an important barrier among GPs when considering pharmacological treatment for the management of hypertension.

Reconstruction and visualization of equivalent currents on a radome using an integral representation formulation

In this paper an inverse source problem is investigated. The measurement set-up is a re∞ector antenna covered by a radome. Equivalent currents are reconstructed on a surface shaped as the radome in order to diagnose the radomes interaction with the radiated fleld. To tackle this inverse source problem an analysis of a full-wave integral representation, with the equivalent currents as unknowns, is used. The extinction theorem and its associated integral equation ensure that the reconstructed currents represent sources within the radome. The axially symmetric experimental set-up reduces the computational complexity of the problem. The resulting linear system is inverted by using a singular value decomposition. We visualize how the presence of the radome alters the components of the equivalent currents. The method enables us to determine the phase shift of the fleld due to the transmission of the radome, i.e., the IPD (insertion phase delay). Also, disturbances due to defects, not observable in the measured near fleld, are localized in the equivalent currents.

Radome Diagnostics—Source Reconstruction of Phase Objects With an Equivalent Currents Approach

Radome diagnostics are acquired in the design process, the delivery control, and in performance verification of repaired and newly developed radomes. A measured near or far field may indicate deviations, e.g., increased side-lobe levels, but the origins of the flaws are not revealed. In this paper, radome diagnostics is performed by visualizing the equivalent surface currents on the 3-D radome body, illuminated from the inside. Three different far-field measurement series at 10 GHz are employed. The measured far field is related to the equivalent surface currents on the radome surface by using a surface integral representation. In addition, a surface integral equation is employed to ensure that the sources are located inside the radome. Phase shifts, insertion phase delays (IPD), caused by patches of dielectric tape attached to the radome surface, are localized. Specifically, patches of various edge sizes (0.5-2.0 free-space wavelengths), and with the smallest thickness corresponding to a phase shift of a couple of degrees are imaged.

Sensitivity Analysis for Antenna Near-Field Imaging

Although imaging and inverse scattering problems have been thoroughly studied during the last century, there is only a partial understanding of these complex problems. Most of the efforts have been placed on the development of efficient inversion algorithms and mathematical uniqueness results. In comparison, there are very few results and a limited knowledge about the information content in the inversion data. In this paper, we provide a mathematical framework for sensitivity analysis of antenna near-field imaging problems, based on the multipole expansion of the electromagnetic field and the Fisher information to quantify the quality of data. By exploiting this framework, a fundamental relation for accuracy and resolution is formulated based on the Crameacuter-Rao bound (CRB). The sensitivity analysis is illustrated using a relevant example with cylindrical measurement data

Trends in out-of-hospital ischaemic heart disease deaths 1992 to 2003 in southern Sweden

Aims: In western countries out-of-hospital ischaemic heart disease (IHD) deaths account for approximately 50–70% of all IHD deaths. The objective was to examine the trends in out-of-hospital IHD deaths in the Region of Skåne in southern Sweden, in different sex- and age-groups. Methods: All 14,347 persons (range 24–110 years) in Skåne who died out-of-hospital between 1992 and 2003 from IHD (I410–I414; I20–I25) as the underlying cause of death. Subjects with previous admission for IHD since 1970 were excluded. Data were retrieved from the Swedish National Cause of Death and Patient Register. Age-standardized IHD mortality rates and trends were calculated using Poisson regression analysis. Results: Age-standardized annual out-of-hospital IHD mortality rates from 1992–2003 decreased in men from 177±13 to 103±9/100,000 inhabitants (−4.7%; p<0.001) and in women from 142±11 to 96±9/100,000 (−2.7%; p<0.001). In men, the annual change in age-standardized IHD mortality rates were −5.3 % (p<0.001), −4.0 % (p<0.001) and −4.7 % (p<0.001), respectively, in the age groups 20–64 years, 65–74 years and ≥75 years. Corresponding figures in women were −4.4 % (p<0.001), −2.4 % (p=0.003) and −2.5 % (p<0.001). The proportion of IHD deaths occurring out-of-hospital was in these age groups 50%, 40% and 35% respectively. Conclusions: In Skåne, out-of-hospital mortality in IHD deaths decreased significantly between 1992 and 2003. The decrease is more pronounced in men than women, and at the end of the study period in 2003, rates were almost equal. The proportion of IHD deaths occurring outside hospital was higher in younger people than in older people.

Source Reconstruction by Far-Field Data for Imaging of Defects in Frequency Selective Radomes

In this letter, an inverse source reconstruction method with great potential in radome diagnostics is presented. Defects, e.g., seams in large radomes, and lattice dislocations in frequency selective surface (FSS) radomes, are inevitable, and their electrical effects demand analysis. Here, defects in a frequency selective radome are analyzed with a method based on an integral formulation. Several far-field measurement series, illuminating different parts of the radome wall at 9.35 GHz, are employed to determine the equivalent surface currents and image the disturbances on the radome surface.