Three kidney systems appear during vertebrate development: the pronephroi, mesonephroi and metanephroi. The pronephric duct is the first or primary ureter of these kidney systems. Its role as a key ...player in the induction of nephrogenic mesenchyme is well established. Here we investigate whether the duct is involved in urine modification using larvae of the freshwater amphibian Ambystoma mexicanum (axolotl) as model.
We investigated structural as well as physiological properties of the pronephric duct. The key elements of our methodology were: using histology, light and transmission electron microscopy as well as confocal laser scanning microscopy on fixed tissue and applying the microperfusion technique on isolated pronephric ducts in combination with single cell microelectrode impalements. Our data show that the fully differentiated pronephric duct is composed of a single layered epithelium consisting of one cell type comparable to the principal cell of the renal collecting duct system. The cells are characterized by a prominent basolateral labyrinth and a relatively smooth apical surface with one central cilium. Cellular impalements demonstrate the presence of apical Na+ and K+ conductances, as well as a large K+ conductance in the basolateral cell membrane. Immunolabeling experiments indicate heavy expression of Na+/K+-ATPase in the basolateral labyrinth.
We propose that the pronephric duct is important for the subsequent modification of urine produced by the pronephros. Our results indicate that it reabsorbs sodium and secretes potassium via channels present in the apical cell membrane with the driving force for ion movement provided by the Na+/K+ pump. This is to our knowledge the first characterization of the pronephric duct, the precursor of the collecting duct system, which provides a model of cell structure and basic mechanisms for ion transport. Such information may be important in understanding the evolution of vertebrate kidney systems and human diseases associated with congenital malformations.
Epiphyseal development was investigated on X‐rays of flippers from 158 harbour porpoises from Danish waters. Development followed a proximodistal pattern similar to what is known in other cetacean ...species. Ossification of epiphyses was rare in the phalanges of the first and fifth digits and in the more distal phalanges of the second, third and fourth digits. Along with the morphology of the first metacarpal and the more distal phalanges this suggested paedomorphosis relative to delphinids. Male and female porpoises showed similar progression of epiphyseal development until approximately the sixth year. From then on, female porpoises showed more progressed development than males. This suggests a higher level of paedomorphosis in the male porpoise. The mechanism behind phocoenid paedomorphosis seems to be progenesis, probably as an adaptation towards a high reproductive rate relative to the delphinids.
Aim: To investigate the association between nurse–patient interaction and sense of coherence among cognitively intact nursing home residents. Method: In a cross-sectional design, data were collected ...in 2017 and 2018 using the Nurse–Patient Interaction Scale (NPIS) and the 13-item Sense of Coherence Scale (SOC-13). Of the 204 cognitively intact nursing home residents who met the inclusion criteria, 188 (92%) participated, representing 27 nursing homes. Multiple regression in a general linear model estimated the possible effects of the 14 NPIS items on SOC-13 sum score, the possible effects of the NPIS (sum score) on SOC-13 (sum score) as well as on the subdimensions of SOC-13, comprehensibility, meaningfulness, and manageability (both without and with adjusting for sex and age). Results: Four of the 14 NPIS items revealed highly significant correlations with SOC-13 (sum score; unadjusted and adjusted for age and gender). Furthermore, the analysis adjusted for age and gender showed significant associations for NPIS (sum score) with SOC-13 (sum score), manageability, and comprehensibility. The correlation between NPIS and meaningfulness was not statistically significant. Conclusion: Nurse–patient interaction is significantly associated with SOC-13 and its subdimensions of comprehensibility and manageability but not meaningfulness. Nurse–patient interaction might be an important resource in relation to residents’ sense of coherence and its subdimensions.
Background and purpose We performed a randomized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem, which is regarded by ...many as the gold standard for comparison of implants due to its extensive documentation.
Patients and methods 150 patients with a mean age of 70 years were randomized, single-blinded, to receive either a cemented Charnley flanged 40 monoblock, stainless steel, vaquasheen surface femoral stem with a 22.2-mm head (n = 30) or a cemented Spectron EF modular, matte, straight, collared, cobalt-chrome femoral stem with a 28-mm femoral head and a roughened proximal third of the stem (n = 120). The patients were followed with repeated radiostereometric analysis for 2 years to assess migration.
Results At 2 years, stem retroversion was 2.3° and 0.7° (p < 0.001) and posterior translation was 0.44 mm and 0.17 mm (p = 0.002) for the Charnley group (n = 26) and the Spectron EF group (n = 74), respectively. Subsidence was 0.26 mm for the Charnley and 0.20 mm for the Spectron EF (p = 0.5).
Interpretation The Spectron EF femoral stem was more stable than the Charnley flanged 40 stem in our study when evaluated at 2 years. In a report from the Norwegian arthroplasty register, the Spectron EF stem had a higher revision rate due to aseptic loosening beyond 5 years than the Charnley. Initial stability is not invariably related to good long-term results. Our results emphasize the importance of prospective long-term follow-up of prosthetic implants in clinical trials and national registries and a stepwise introduction of implants.
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