[Oversupplied? Undersupplied? - The Perspective of Local Governments of the Federal State of Baden-Württemberg: A Contribution to the Discussion of Close-to-Home Health Care]. / Überversorgt? Unterversorgt? - die Sicht von Bürgermeistern in Baden-Württemberg: Ein Beitrag zur Diskussion um die wohnortnahe medizinische Versorgung.

BACKGROUND: The ageing of physicians working in ambulatory care make regional health planning a challenging task. This study examines the current supply of general practitioners (GP) within the communities from the perspective of mayors. The information gained on a community level can be used when discussing over- and undersupply as well as future health care planning. METHODS: A questionnaire was sent to all 1101 mayors of the Federal state of Baden-Württemberg (BW) in May 2011. For the evaluation of the location of the communities, subjective ratings by the mayors were compared with official criteria, provided by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR). RESULTS: The participation rate was 63% (n=698). According to the mayors about 70% (n=468) were located in a rural area, according to BBSR criteria were about 26% (n=177) of answers given by rural communities. Of the participating mayors about 54% (n=355) stated that their community is cared for merely by GPs. From this information there was a locally experienced undersupply of GPs calculated for 13.5% (n=86) of the communities. This affected rural as well as non-rural communities. In communities up to 20 000 inhabitants, the ratio between GPs and other specialists seems to be 60:40 whereas in bigger cities the proportion of other specialists appears to be much higher. CONCLUSION: Half of the participating communities seem to not have a practicing specialised physician. An accumulation of specialised physicians in larger cities was reported. The GP shortage appears to mainly be experienced subjectively. Regarding the location (urban vs. rural) of the community, subjective views differ distinctly from the BBSR criteria. This discrepancy could influence a community's marketing strategy when competing for new physicians.

[Perceptions of the local government about the primary care physicians shortage - a survey among mayors in the Federal State of Baden-Wuerttemberg]. / Die Sichtweise der kommunalen Ebene über den Hausärztemangel - eine Befragung von Bürgermeistern in Baden-Württemberg.

BACKGROUND: Local governments have a crucial role in dealing with the primary care physicians shortage (PS). The aim of this study is to evaluate the perspectives and experiences of the local mayors on this issue. METHODS: In May 2011, all 1101 mayors in the Federal State of Baden-Wuerttemberg (BW) were invited to participate in the study by filling out a survey developed by the authors. Data were analysed descriptively. RESULTS: Of the contacted mayors in BW, 63% (n=698) responded. More than 90% of the participants consider it their duty to ensure future primary care. 16% experienced local practice closures due to PS. The infrastructure provided by the communities seems to be at a high level, whereas emergency practices exist in only 15% of the communities at present. Supportive actions to attract new GPs are evaluated as appropriate by almost half of the participants. CONCLUSIONS: The PS topic is of high relevance for communities in BW. In order to gain future physicians for their region, the majority of the communities are maintaining a high level of infrastructure and are willing to offer more actions. The young generation physicians need to be informed about these existing conditions. Innovative ideas should be implemented in individual communities as pilot projects.

pH regulation in horizontal cells of the skate retina.

To examine the mechanisms by which horizontal cells regulate intracellular pH (pHi), measurements were recorded from isolated cells enzymatically dissociated from the skate retina utilizing the pH-sensitive dye BCECF. In a HCO3--containing Ringer solution, steady-state pHi was 7.32+/-0.13 (mean+/-S.D., n=70). Recovery from acidification was examined using the NH4+ prepulse technique. When NH4+ was removed from the extracellular solution, pHi dropped rapidly to approximately 0.3 pH units below the initial baseline, and then recovered at an initial rate of approximately 0.072 pH units/min. During recovery of pHi after the acid load, the removal of Na+ or the addition of amiloride from a HCO3--free extracellular solution reduced the rate of recovery by 79%+/-11% and 69%+/-14%, respectively. In the presence of DIDS, which inhibits primarily anion transport, or during the removal of Na+, the recovery from acidification was reduced by 83%+/-10% and 70%+/-11%, respectively, as compared to the control value in HCO3--containing solution. These results suggest that the skate horizontal cell possesses a Na/H exchanger as well as a Na+-and HCO3--dependent mechanism for removal of excess acid. Removal of HCO3- or Cl- from the extracellular solution had little effect on pHi, but removing external Na+ induced a marked decrease in pHi that fell at an initial rate of approximately 0.3 pH units min-1. This rate of acidification was decreased by 58%+/-19% in the presence of DIDS (500 micron) and reduced by 28%+/-13% with the addition of amiloride (2 mm). Thus, Na- and HCO3-dependent transport was about 2-fold more active than Na/H exchange during low Na+-induced acidification. The intrinsic pH-buffer capacity, determined from the pHi change induced by incremental reductions in the [NH4+] of the extracellular solution, was 24.2 mm/pH unit at the horizontal cell's resting pHi. Moreover, pHi was relatively insensitive to changes in membrane potential; in experiments under whole-cell voltage clamp (-70 mV), intracellular pH remained constant during depolarizing voltage swings to -30 mV or +30 mV, as well as during hyperpolarizing pulses to -90 or -110 mV.

Sodium-calcium exchanger in cultured human retinal pigment epithelium.

Regulation of intracellular free Ca2+ concentration ([Ca2+]i) by an Na+/Ca2+ exchanger was studied in cultures of human retinal pigment epithelial cells using Ca(2+)-indicator dyes (fura-2 and fluo-3) and digital fluorescence imaging. Mean resting [Ca2+]i of cultured RPE in a control Ringer solution was 189 +/- 16 nM. Replacing extracellular Na+ with N-methyl-D-glucamine elicited a two-fold rise in [Ca2+]i; the magnitude of the [Na+]o-free-induced rise in [Ca2+]i varied as a function of extracellular [Ca2+]. The [Na+]o-free response was not significantly affected by the Ca2+ channel blocker nifedipine, or by pretreatment with thapsigargin which depletes intracellular Ca2+ stores. By contrast, the [Na+]o-free-induced rise in [Ca2+]i was significantly reduced by CBDMB, an amiloride derivative that is highly selective for Na+/Ca2+ exchange inhibition. These findings indicate that removal of extracellular Na+ promotes net [Ca2+]i gain via Na+/Ca2+ exchange. Western and Northern blot analyses, respectively, confirmed the presence of Na+/Ca2+ exchanger protein and mRNA in cultures of human RPE. Specifically, Western blot analysis of whole cell lysates of cultured RPE using a polyclonal antibody made against the canine cardiac exchanger identified a major band at approximately 126 kD. Northern blot analysis of total human RPE RNA using a restriction fragment cRNA probe coding for the canine cardiac Na+/Ca2+ exchanger showed that the major exchanger-related transcript was approximately 6.8 kb. In sum, our findings demonstrate the presence of a cardiac-exchanger-related transcript was approximately 6.8 kb. In sum, our findings demonstrate the presence of a cardiac-type Na+/Ca2+ exchanger in cultures of human RPE.

GABA transport and calcium dynamics in horizontal cells from the skate retina.

1. Changes in intracellular calcium concentration [Ca2+]i in response to extracellularly applied gamma-aminobutyric acid (GABA) were studied in isolated horizontal cells from the all-rod skate retina. 2. Calcium measurements were made using fura-2 AM, both with and without whole-cell voltage clamp. Superfusion with GABA, in the absence of voltage clamp, resulted in an increase in [Ca2+]i; the threshold for detection was approximately 50 microM GABA, and a maximal response was elicited by 500 microM GABA. 3. The rise in [Ca2+]i was not mimicked by baclofen nor was it blocked by phaclofen, picrotoxin or bicuculline. However, the GABA-induced [Ca2+]i increase was completely abolished when extracellular sodium was replaced with N-methyl-D-glucamine. 4. With the horizontal cell voltage clamped at -70 mV, GABA evoked a large inward current, but there was no concomitant change in [Ca2+]i. Nifedipine, which blocks L-type voltage-gated Ca2+ channels, suppressed the GABA-induced increase in [Ca2+]i. These findings suggest that the calcium response was initiated by GABA activation of sodium dependent electrogenic transport, and that the resultant depolarization led to the opening of voltage-gated Ca2+ channels, and a rise in [Ca2+]i. 5. The GABA-induced influx of calcium appears not to have been the sole source of the calcium increase. The GABA-induced rise in [Ca2+]i was reduced by dantrolene, indicating that internal Ca2+ stores contributed to the GABA-mediated Ca2+ response. 6. These observations demonstrate that activation of the GABA transporter induces changes in [Ca2+]i which may have important implications for the functional properties of horizontal cells.

Oxygen consumption in the isolated toad retina.

Retinal O2 utilization was studied to identify the O2 consuming processes in the retina and the spatial distribution of those processes. Neural retina, retinal pigment epithelium and choroid were dissected from the toad eye and superfused with an oxygenated Ringer's solution. Double-barreled microelectrodes were used to measure O2 and local voltage simultaneously within the retina in both light and dark adaptation. The profile of PO2 was measured during a withdrawal of the electrode tip across the retinal pigment epithelium and through the neural retina. The PO2 decreased through the distal retina, reaching a minimum in the inner segment or outer nuclear layer, and then increased steadily through the proximal retina. From fitting PO2 profiles measured in the dark-adapted retina to a three-layer diffusion model, O2 consumption was found to be 1.0 +/- 0.4 and 0.4 +/- 0.3 ml O2 (100 g min)-1 in the outer and inner halves of the retina, respectively. Light decreased consumption in both halves of the retina. In steady illumination (500 nm) that saturated the ERG b- and c-waves, O2 utilization decreased significantly to 48% and 68% of the dark values in the outer and inner retina, respectively. When Na+ was removed from the superfusate to inhibit the photoreceptor Na+/K+ pump, O2 consumption in the outer retina decreased by about the same amount as in light, but O2 consumption in the inner retina was not significantly affected.

Light-evoked oxygen responses in the isolated toad retina.

Transient changes in retinal oxygen in response to light stimuli were studied to further understand the light-evoked change in oxygen consumption. Double-barreled microelectrodes, which measured oxygen and local voltage simultaneously, were positioned near the photoreceptor inner segments of the toad neural retina-retinal pigment epithelium-choroid preparation. Light-evoked oxygen responses were measured in a normal [Na+] solution, and in a test solution with lowered extracellular [Na+] to inhibit Na+/K+ pumping. Under the normal [Na+] condition, retinal oxygen tension increased in response to light indicating that oxygen utilization had decreased. When the Na+ concentration was lowered in the retina, the oxygen tension decreased in response to light, indicating an increase in oxygen utilization which was smaller than the Na+/K+ pump effect and therefore masked under normal conditions. The increase in oxygen utilization in lowered [Na+] was suppressed by adding 0.7 mM 3-isobutyl-1-methyl-xanthine, a phosphodiesterase inhibitor, suggesting that the response was largely due to hydrolysis and subsequent resynthesis of cyclic GMP. Results of fitting the light-evoked responses to exponential functions suggested that the decrease in oxygen consumption caused by slowing of the photoreceptor Na+/K+ ATPase had a time constant between 130 and 180 sec and that the increase in oxygen utilization from increased cyclic GMP synthesis was faster.