5-Hydroxytryptamine in the enterochromaffin cells of the guinea pig alimentary tract

Summary The histoohemical properties of the EC in the guinea pig alimentary canal were studied using the paraformaldehyde-induced fluorescence and five ordinary staining reactions. The fluorescence reaction was observed to be the most sensitive and specific one in the demonstration of the EC. Using the fluorescence and argyrophil techniques concomitantly, it was stated that all the fluorescent EC had also argyrophil properties. These observations lend further support to the author's earlier statement (Penttilä), 1966) that there is only one principal type of EC in the gastrointestinal tract. The argentaffin and other staining reactions were not able to colour all the EC, except in the duodenum.In the quantitative part of this study the EC number (No./mm) and the 5-HT (g/g) concentration were determined from the adjacent tissue pieces. Both quantities were absolutely at its highest in the duodenum and decreased in the caudal direction of the intestine. In the stomach the values were of the same magnitude as in the middle part of the intestinal tract. In the oesophagus there were no EC and the 5-HT content was negligible in comparison to the other gastrointestinal sites. The correlation between the EC number and the 5-HT content was highly significant from the stomach to the rectum. The 5-HT content per one EC was the largest in the duodenum. Comparing the histochemical and quantitative results the 5-HT location in the enterochromaffin system was discussed.     

Nuclear and cytoplasmic microfilaments in the pineal chief cells of the rat

Summary The presence of identical groups of parallel microfilaments in the nucleus and in the cytoplasm of the rat epiphyseal chief cells are described. The areas of microfilaments are not surrounded by any membranes and the single filaments are about 70–80 Å in diameter and vary largely in length. At higher magnification the filaments are shown to be composed of an inner light and outer dark zone. Since the filaments in the nucleus and in the cytoplasm are morphologically identical, they are suggested to originate in the same part of the cell and thus to be involved in the nucleo-cytoplasmic interaction.

---

Zusammenfassung Die Anwesenheit von gleichartigen Gruppen paralleler Mikrofilamente in Kern und Zytoplasma von Haupt-Zellen in der Rattenepiphyse wird beschrieben. Die Mikrofilamentareale werden nicht von Membranen umgeben; die einzelnen Filamente weisen einen Durchmesser von etwa 70–80 A auf und variieren stark in der Länge.Bei starker Vergrößerung zeigt sich, daß die Filamente aus einem inneren hellen und äußeren dunklen Streifen zusammengesetzt sind.Da die Filamente im Kern und im Zytoplasma morphologisch identisch sind, kann man fragen, ob sie am selben Ort in der Zelle entstehen und folglich in der Wechselwirkung von Kern und Zytoplasma eine Rolle spielen.

     

Heparin binding to the urokinase kringle domain.

The binding of urokinase to immobilized heparin and dextran sulfate was studied using activity assays of the bound urokinase. The markedly higher binding observed with high M(r) urokinase compared to low M(r) urokinase indicated a role for the amino-terminal fragment (ATF). This was confirmed by the use of inactive truncated urokinase and monoclonal antibodies specific for the ATF in competition assays of urokinase binding. Antibody competition assays suggested a site in the kringle domain, and a synthetic decapeptide Arg-52-Trp-62 from the kringle sequence (kringle numbering convention) was competitive in assays of urokinase binding to dextran sulfate and heparin. Heparin binding to the urokinase kringle was unambiguously demonstrated via 1H NMR spectroscopy at 500 MHz. Effective equilibrium association constants (K(a)*) were determined for the interaction of isolated kringle fragment and low M(r) heparin at pH 7.2. The binding was strong in salt-free 2H2O (K(a)* approximately 57 mM-1) and remained significant in 0.15 M NaCl (K(a)* approximately 12 mM-1), supporting a potential physiological role for the interaction. This is the first demonstration of a function for the kringle domain of urokinase, and it suggests that while the classical kringle structure has specificity for lysine binding, there may also exist a class of kringles with affinity for polyanion binding.     

An approach to mapping haplotype-specific recombination sites in human MHC class III

Studies of the major histocompatibility complex (MHC) in mouse indicate that the recombination sites are not randomly distributed and their occurrence is haplotype-dependent. No data concerning haplotype-specific recombination sites in human are available due to the low number of informative families. To investigate haplotype-specific recombination sites in human MHC, we here describe an approach based on identification of recombinant haplotypes derived from one conserved haplotype at the population level. The recombination sites were mapped by comparing polymorphic markers between the recombinant and assumed original haplotypes. We tested this approach on the extended haplotype HLA A3; B47; Bf ^* F; C4A ^* 1; C4B ^* Q0; DR7, which is most suitable for this analysis. First, it carries a number of rare markers, and second, the haplotype, albeit rare in the general population, is frequent in patients with 21-hydroxylase (21OH) defect. We observed recombinants derived from this haplotype in patients with 21OH defect. All these haplotypes had the centromeric part (from Bf to DR) identical to the original haplotype, but they differed in HLA A and B. We therefore assumed that they underwent recombinations in the segment that separates the Bf and HLA B genes. Polymorphic markers indicated that all break points mapped to two segments near the TNF locus. This approach makes possible the mapping of preferential recombination sites in different haplotypes.     

The effects of temperature and adrenergic agonists on cardiac myocytes of perch (Perca fluviatilis) in cell culture conditions

1. 1. Isolated cardiac myocytes of perch, Perca fluviatilis, were kept in culture conditions for 1–2 months at 12 or 22°C. In the culture most myocytes flattened, lost their spindle-shaped morphology, protruded pseudopod-like branches and many of them started visible contractions in 1–2 weeks and continued beating for several months. Myocytes did not divide in the sparse cell population used. Typical intracellular structures could be seen in electron micrographs still after 1–2 months, but the sarcoplasmic organization became gradually more irregular in the culture.

2. 2. Beat rates showed linear temperature relationship on the Arrhenius plot. Myocytes cultivated at 22°C showed higher frequencies and slightly less dependence on temperature than myocytes cultivated at 12°C (apparent activation energies (E_a) 86 and 107 kJ/mol, respectively).

3. 3. Temperature dependence of frequencies was related to the presence of added serum or adrenergic agonists: β-adrenergic agonists increased the frequencies and rendered the cells less dependent on temperature; apparent activation energy was 43 kJ/mol for isoprenaline or adrenaline and 108 kJ/mol for noradrenaline and control group.

4. 4. Heat tolerance was greater in myocytes cultivated at 22°C than in myocytes cultivated at 12°C, and the change in tolerance appeared in 12 h after the alteration of culture temperature and the increased tolerance was persistent after that.

5. 5. It is suggested, that the processes of quick heat-hardening and of slower but persistent heat resistance acclimation developed in these cells in culture conditions but not the capacity acclimation, which seems to be dependent on adrenergic regulation of beat rate.

Effects of bovine colostrum supplementation on serum IGF-I, IgG, hormone, and saliva IgA during training

Mero, Antti, Heidi Miikkulainen, Jarmo Riski, RaimoPakkanen, Jouni Aalto, and Timo Takala. Effects of bovinecolostrum supplementation on serum IGF-I, IgG, hormone, and saliva IgAduring training. J. Appl. Physiol.83(4): 1144-1151, 1997.The purpose of this study was to examinethe effects of bovine colostrum supplementation (Bioenervi) on seruminsulin-like growth factor I (IGF-I), immunoglobulin G, hormone, andamino acid and saliva immunoglobulin A concentrations during a strengthand speed training period. Nine male sprinters and jumpersunderwent three randomized experimental training treatments of 8 daysseparated by 13 days. The only difference in the treatments was thedrink of 125 ml consumed per day. Posttraining increases were noticedfor serum IGF-I in the 25-ml Bioenervi treatment (125 ml contained 25 ml Bioenervi) and especially in the 125-ml Bioenervi treatment (125 mlcontained 125 ml Bioenervi) compared with the placebo (normal milkwhey) treatment (P < 0.05). The change in IGF-I concentration during the 8-day periods correlated positively with the change in insulin concentration during the sameperiods with 25-ml Bioenervi treatment(r = 0.68;P = 0.045) and with 125-ml Bioenervitreatment (r = 0.69;P = 0.038). Serum immunoglobulin G,hormone, and amino acid and saliva immunoglobulin A responses weresimilar during the three treatments. It appears that a bovine colostrumsupplement (Bioenervi) may increase serum IGF-I concentration inathletes during strength and speed training.

     

Extracellular matrix proteins of human epidermal keratinocytes and feeder 3T3 cells

Cultures of human epidermal keratinocytes obtained from adult epidermis were initiated using irradiated BALB/3T3 cells as feeder layers. At different stages of confluence of the epidermal islands, feeder cells were removed and the extracellular matrix proteins of both pure component cells and cocultures were analyzed biochemically and by immunochemical methods and compared to those of skin fibroblasts of the same donors. The keratinocytes synthesized and secreted fibronectin and small amounts of laminin and type IV collagen. In addition, a nondisulfide-linked collagenous polypeptide (Mr = 120,000) was synthesized by the keratinocytes and was confined to the cell layers. Collagenous polypeptides with Mr = 120,000 were also synthesized by organ cultures of epidermal tissue and were detected in its acid or detergent extracts but again no secretion to culture medium was found. The Mr = 120,000 collagen had biochemical and immunological properties distinct from those of types I-V collagens. In immunofluorescence of keratinocyte cultures, fibronectin staining was prominent in the lining marginal cells of the expanding periphery of the epidermal cell islands but was not detected in the terminally differentiating cells in the upper layers of stratified colonies. Very little type IV collagen was found deposited in pericellular matrix form by the keratinocytes. In contrast, the mouse 3T3 feeder cells were found to produce both type IV collagen and laminin in addition to the previously identified connective tissue glycoproteins of fibroblasts, interstitial procollagens, and fibronectin. Basement membrane collagen of the 3T3 cells was found deposited as apparently unprocessed procollagen alpha 1(IV) and alpha 2(IV) chains. The production in culture conditions of basal lamina glycoproteins by the fibroblastic feeder cells may promote the attachment and growth of the cocultured keratinocytes.     

Thermoacclimatory changes in blood oxygen binding properties and gill secondary lamellar structure ofSalmo gairdneri

Summary The blood oxygen binding properties and gill secondary lamellar structure of rainbow trout acclimated to several temperatures were studied. The blood oxygen carrying capacity decreased as acclimation temperature increased from 2 to 15 °C; the decrease was probably caused by an increase in plasma volume. Also the blood oxygen affinity decreased as the acclimation temperature increased from 2 to 15 °C. This change had no effect on the oxygen loading in gills, since the efferent arterial oxygen tension was adequate for approximately 100% erythrocytic O₂ saturation at all acclimation temperatures, but facilitated the oxygen unloading in tissues. At the highest acclimation temperature (18 °C) the oxygen loading in gills was facilitated by the changes in the secondary lamellar structure; the proportion of erythrocytes in the secondary lamellar capillaries was higher than at the other acclimation temperatures (2 and 10 °C).     

Complexing of glycofuranosides with calcium ion,and its effect on their acid-catalysed solvolysis

Stability constants for the calcium-ion complexes of several methyl aldo-furanosides have been determined in aqueous solution by using a potentiostatic technique with an electrode that is selective for calcium ions. The results obtained have been verified by examining the chromatographic behaviour of the compounds on a strong cation-exchange resin in the Ca²⁺ form. The rate constants for the acid-catalyzed hydrolysis and methanolysis of a few 4-chlorophenyl aldofuranosides having different complexing abilities have been determined at various concentrations of calcium chloride. The dependences of the observed salt effects on the complexing ability of the substrate are discussed.