Membrane-associated carbonic anhydrase IV in skeletal muscle: subcellular localization

 Carbonic anhydrase IV (CA IV) was examined by light microscopy and electron microscopy in rat soleus muscle. Semithin sections of aldehyde-fixed Epon-embedded muscle were stained with rabbit anti-rat lung CA IV and the avidin-biotin-peroxidase complex. With this technique, capillaries and sarcolemma showed positive CA IV staining. For electron microscopy, rat soleus specimens were aldehyde-fixed, with or without subsequent osmication, and embedded in Epon. Ultrathin sections were immunostained with anti-rat lung CA IV/immunogold. Omitting osmium allowed ample antigen-antibody reactions but could not prevent the release of glycosylphosphatidylinositol-anchored CA IV from the membranes, which led to apparent background staining. Postosmication significantly reduced tissue antigenicity but kept the antigen bound to the membranes and thus allowed a very precise localization of CA IV. By electron microscopy, membrane-bound CA IV is found to be associated with capillary endothelium, sarcolemma, and sarcoplasmic reticulum (SR). Conceivably, the presence of SR staining in ultrathin sections and its absence in semithin sections reflect a problem of accessibility of the antigenic sites. Accepted: 17 May 1996     

How many general surgeons do you need in rural areas? Three approaches to physician resource planning in southern Manitoba.

OBJECTIVE: To assess critically the results of using three different approaches to planning for the number of general surgeons in rural areas. DESIGN: Estimates of the number of general surgeons needed using a ratio approach, a and a population-needs-based approach. SETTING: Rural southern Manitoba. OUTCOME MEASURE: Number of general surgeons needed. RESULTS: The ratio approach supported the recruitment of 7.8 to 14.5 additional general surgeons to rural southern Manitoba. The repatriation approach suggested that the area might support five additional general surgeons, if residents could be persuaded to undergo their surgery closer to home. The population-needs-based approach suggested that the health status of area residents was similar to that of residents of other areas of the province and that they had a higher rate of surgery than residents of other areas; no additional surgeons were apparently needed. CONCLUSIONS: Each method has certain advantages, and none is necessarily useful in isolation. Hence, the most effective approach to planning for general surgeons is likely a combination of all three methods. Other factors that may be important include the type of payment structure and the need for professional groups to monitor variations in rates of surgery.     

Barcoding of Central European Cryptops centipedes reveals large interspecific distances with ghost lineages and new species records from Germany and Austria (Chilopoda,Scolopendromorpha)

In order to evaluate the diversity of Central European Myriapoda species in the course of the German Barcode of Life project, 61 cytochrome c oxidase I sequences of the genus Cryptops Leach, 1815, a centipede genus of the order Scolopendromorpha, were successfully sequenced and analyzed. One sequence of Scolopendra cingulata Latreille, 1829 and one of Theatops erythrocephalus Koch, 1847 were utilized as outgroups. Instead of the expected three species (Cryptops parisi Brolemann, 1920; Cryptops anomalans Newport, 1844; Cryptops hortensis (Donovan, 1810)), analyzed samples included eight to ten species. Of the eight clearly distinguishable morphospecies of Cryptops, five (Cryptops parisi; Cryptops croaticus Verhoeff, 1931; Cryptops anomalans; Cryptops umbricus Verhoeff, 1931; Cryptops hortensis) could be tentatively determined to species level, while a further three remain undetermined (one each from Germany, Austria and Croatia, and Slovenia). Cryptops croaticus is recorded for the first time from Austria. A single specimen (previously suspected as being Cryptops anomalans), was redetermined as Cryptops umbricus Verhoeff, 1931, a first record for Germany. All analyzed Cryptops species are monophyletic and show large genetic distances from one another (p-distances of 13.7–22.2%). Clear barcoding gaps are present in lineages represented by >10 specimens, highlighting the usefulness of the barcoding method for evaluating species diversity in centipedes. German specimens formally assigned to Cryptops parisi are divided into three clades differing by 8.4–11.3% from one another; their intra-lineage genetic distance is much lower at 0–1.1%. The three clades are geographically separate, indicating that they might represent distinct species. Aside from Cryptops parisi, intraspecific distances of Cryptops spp. in Central Europe are low (<3.3%).     

Electrical resistance measurements on cerebral capillary endothelial cells — a new technique to study small surface areas

We present a new method which allows resistance measurements in selected cell monolayer areas with a size of less than one mm². Up to now cell-covered macroscopic filters with areas up to 5 cm² have been used giving reliable results only in the absence of inhomogeneities or contaminating cells. The new measuring device is posed on the microscope optic to allow an optical characterization of the measuring area and enables us to scan the cell-covered filter. This method has been applied to determine a reversible modulation of the tightness of intercellular contacts between epithelial or endothelial cells in culture. Tight junction resistance is modulated by Ca²⁺ and basic amino acids in cultured porcine cerebral microvascular endothelial cells that represent the blood-brain barrier.     

First results of the German Barcode of Life (GBOL) – Myriapoda project: Cryptic lineages in German Stenotaenia linearis (Koch, 1835) (Chilopoda,Geophilomorpha)

As part of the German Barcode of Life (GBOL) Myriapoda program, which aims to sequence the COI barcoding fragment for 2000 specimens of Germany’s 200 myriapod species in the near future, 44 sequences of the centipede order Geophilomorpha are analyzed. The analyses are limited to the genera Geophilus Leach, 1814 and Stenotaenia Koch, 1847 and include a total of six species. A special focus is Stenotaenia, of which 19 specimens from southern, western and eastern Germany could be successfully sequenced. The Stenotaenia data shows the presence of three to four vastly different (13.7–16.7% p-distance) lineages of the genus in Germany. At least two of the three lineages show a wide distribution across Germany, only the lineage including topotypes of Stenotaenia linearis shows a more restricted distribution in southern Germany. In a maximum likelihood phylogenetic analysis the Italian species Stenotaenia ‘sorrentina’ (Attems, 1903) groups with the different German Stenotaenia linearis clades. The strongly different Stenotaenia linearis lineages within Germany, independent of geography, are a strong hint for the presence of additional, cryptic Stenotaenia species in Germany.