Technology of pre-programmable insulin delivery systems: continuous subcutaneous insulin infusion.

Dual-rate continuous subcutaneous insulin infusion was performed with a specially adapted Mill Hill Infuser. The infuser delivers 2 rates, a slow rate of ca. 50 microliter/h and an eightfold higher rate, designed to cover the increased requirement during meals. The high rate is engaged by pressing a button on the side of the pump, and returns automatically to the basal level after 17 min. Insulin is delivered to the subcutaneous side by a nylon cannula.     

Live imaging of <Emphasis Type="Italic">Drosophila</Emphasis>gonad formation reveals roles for Six4 in regulating germline and somatic cell migration

Background  

Movement of cells, either as amoeboid individuals or in organised groups, is a key feature of organ formation. Both modes of migration occur during Drosophila embryonic gonad development, which therefore provides a paradigm for understanding the contribution of these processes to organ morphogenesis. Gonads of Drosophila are formed from three distinct cell types: primordial germ cells (PGCs), somatic gonadal precursors (SGPs), and in males, male-specific somatic gonadal precursors (msSGPs). These originate in distinct locations and migrate to associate in two intermingled clusters which then compact to form the spherical primitive gonads. PGC movements are well studied, but much less is known of the migratory events and other interactions undergone by their somatic partners. These appear to move in organised groups like, for example, lateral line cells in zebra fish or Drosophila ovarian border cells.     

Ultrastructural observations of spermatozoa of several tetragnathid spiders with phylogenetic implications (Araneae, Tetragnathidae)

The present study reports on the ultrastructure of spermatozoa and spermatogenesis of 12 tetragnathid spiders (10 Tetragnatha species [T. boydi, T. dearmata, T. extensa, T. montana, T. nigrita, T. obtusa, T. pinicola, T. reimoseri, T. shoshone, T. striata]; Pachygnatha listeri and Metellina segmentata). All species develop typical cleistospermia with a coiled nucleus in the center and a coiled axoneme in the periphery of the cell. Remarkable differences in the sperm ultrastructure of the investigated species comprise the shape of the main sperm cell components (nucleus, acrosomal complex, implantation fossa, and centriolar complex). Within the observed Tetragnatha species, three types of sperms were characterized: T. montana-type, T. boydi-type, and T. striata-type. The highly derivative T. montana-type is characterized by the following remarkable features: an extremely elongated nucleus, shaped like a corkscrew and twisted around the axoneme (before coiling); a deep implantation fossa; a corkscrew-shaped acrosomal vacuole; after the coiling process, the nucleus is coiled five to six times in the center of the spermatozoon and the axoneme is coiled five to six times peripheral to the nucleus. The T. boydi-type hardly differs from the T. montana-type, but is remarkable due to the triangular-shaped nucleus (in cross section). The T. striata-type differs especially by a peculiar acrosomal vacuole with a long, slightly curved process and a short appendix, as well as a nucleus that describes only three loose coils around the axoneme (before coiling). The spermatozoa of Pachygnatha listeri and especially Metellina segmentata differ strikingly from the described Tetragnatha-types and are similar to more primitive araneomorph spermatozoa, such as Hypochilus pococki. The described Tetragnatha-types completely correspond with Okuma's (1988a,b, J Fac Agr Kyushu U 32:165-181, 32:183-213) classification of Tetragnatha species. Furthermore, our results suggest an early derivative systematic position of Pachygnatha within Tetragnathinae and the position of Metellina within the Tetragnathidae.     

Potentiometric sensor for atrazine based on a molecular imprinted membrane

A molecular imprinted polymer (MIP) membrane for atrazine, not containing macropores, was synthesized and implemented in a potentiometric sensor. It is expected to work like a solid ISE (where the specific carrier are the imprinted sites) the specific carrier being the imprinted site. The active ion is the protonated atrazine, positively charged. To form this species the determination is carried out in acidic solution at pH lower than 1.8, in which atrazine is prevalently monoprotonated. At these conditions the membrane potential increases with atrazine concentration over a wide concentration range (3 x 10(-5) to 1 x 10(-3)M). The slope of the function E versus logc is about 25 mV/decade, showing that the atrazine form sorbed on MIP is the biprotonated one. The detection limit is determined by the relatively high concentration of atrazine released by the membrane in the sample solution at the considered conditions. It seems to be independent of the atrazine concentration in the internal solution of the sensor, but it depends on the acidity of the solution. The response time is less than 10s and the sensor can be used for more than 2 months without any divergence.     

Sequence variant (CTAGGG)n in the human telomere favors a G-quadruplex structure containing a G·C·G·C tetrad

Short contiguous arrays of variant CTAGGG repeats in the human telomere are unstable in the male germline and somatic cells, suggesting formation of unusual structures by this repeat type. Here, we report on the structure of an intramolecular G-quadruplex formed by DNA sequences containing four human telomeric variant CTAGGG repeats in potassium solution. Our results reveal a new robust antiparallel G-quadruplex fold involving two G-tetrads sandwiched between a G·C base pair and a G·C·G·C tetrad, which could represent a new platform for drug design targeted to human telomeric DNA.     

Synthesis and stereochemical effects of pyrrolidinyl-acetylenic thieno[3,2-d]pyrimidines as EGFR and ErbB-2 inhibitors

A novel class of pyrrolidinyl-acetyleneic thieno[3,2-d]pyrimidines has been identified which potently inhibit the EGFR and ErbB-2 receptor tyrosine kinases. Synthetic modifications of the pyrrolidine carbamate moiety result in a range of effects on enzyme and cellular potency. In addition, the impact of the absolute stereochemical configuration on cellular potency and oral mouse pharmacokinetics is described.     

Ultrastructure of spermatozoa of Solifuges (Arachnida, Solifugae): possible characters for their phylogeny?

The ultrastructure of spermatozoa is a widely accepted source of characters for phylogenetic studies. In this study the fine structure of sperm cells of representatives of six different New and Old World families (Ammotrechidae, Daesiidae, Eremobatidae, Galeodidae, Karschiidae, Solpugidae) of solifuges (Arachnida, Solifugae) were investigated in order to reveal putative characters suitable for subsequent systematic and phylogenetic analyses. The spermatozoa of solifuges represent a relatively simple type of sperm cells. In general, their spermatozoa are roundish, oval shaped (Ammotrechidae, Daesiidae, Eremobatidae, Solpugidae) or plate-shaped (Karschiidae) with or without membrane protuberances and devoid of a flagellum. Only in Galeodidae, very conspicuous thin and elongated sperm cells occur. The spermatozoa either occur as single cells (Eremobatidae, Solpugidae) or in groups of loose knit cells (Ammotrechidae) or in highly ordered groups (Karschiidae). In contrast to the other families studied here, within the Galeodidae and in the genus Blossia (Daesiidae) sperm cells surrounded by a secretion sheath, clearly representing coenospermia, could be observed.