A model for the embryological instruction of the branchial arteries

It is difficult to teach students about the embryological transformation of the branchial arteries. In mammals, six pairs of branchial arteries develop, but all are not present at the same embryological stage. The first, second, fifth and a part of right sixth branchial artery disappear early in embryological development. The remaining third, fourth and sixth branchial arteries mainly constitute the arterial system of the breast. The aorta and pulmonary trunk are derived from the truncus arteriosus. Because of the complexity of this developmental process, we have devised a user-friendly model in order to assist with educational presentations. In this model, the shrinkage of a vessel has been represented by inserting a wire inside of the hose representing the artery. Degenerated or disappearing parts of the vessel are removable by using hooks and Velcro tape. Branchial arteries, truncus arteriosus, aortic sac and dorsal arteries are represented by different colors. The descent of the heart is represented by the relational change between larynx and heart. Additionally we represented the vagus nerve and recurrent laryngeal nerve by using strings. The right vagus nerve can move dorsally and the left ventrally by rotating the digestive tract. The right recurrent laryngeal nerve can move superiorly to hook around the right subclavian artery, and left recurrent laryngeal nerve can hook around the ductus arteriosus formed by the left sixth branchial artery.     

Biotin deficiency in amino acid formula nutrition for an infant with milk protein allergy]

We reported a 4-month-old girl with biotin deficiency caused by amino acid formula. Two weeks after birth, she was diagnosed as having a milk protein allergy. After switching to amino acid formula from usual formula, her symptoms and laboratory findings became normal. About three weeks after the beginning of amino acid formula, she developed intractable skin erosions around the eyes, mouth, neck, and anogenital area. By measuring concentrations of some trace elements, she was diagnosed as having a biotin deficit, because of the organic aciduria and undetectable serum biotin concentration. Her serum biotinidase level was normal. Upon administration of oral biotin supplementation, all her symptoms and laboratory findings were dramatically improved. Since amino acid formula contains very few biotin, we should pay attention to biotin deficiency when infants receiving amino acid formula.     

Meu10 is required for spore wall maturation in Schizosaccharomyces pombe

BACKGROUND: Many genes are meiosis and/or sporulation-specifically transcribed during this process. Isolation and analysis of these genes might help us to understand how meiosis and sporulation are regulated. For this purpose, we have isolated a large number of cDNA clones from Schizosaccharomyces pombe whose expression is up-regulated during meiosis. RESULTS: We have isolated meu10+ gene, which encodes 416 amino acids and bears homology to SPS2 of Saccharomyces cerevisiae. A strain whose meu10+ gene has been deleted forms no viable spores. Thin-section electron micrographs showed that the meu10Delta strain has abnormally formed spore walls, and then they disrupt, allowing cytoplasmic material to escape. The Meu10-GFP fusion protein is localized to the spore periphery, thereafter returned to the cytoplasm after sporulation. Meu10-GFP localization to the spore wall was almost normal in the bgs2Delta or chs1Delta mutants that lack 1,3-beta-glucan or chitin, respectively. In contrast, 1,3-beta-glucan is abnormally localized in meu10Delta cells. Meu10 has an N-terminal domain with homology to the mammalian insulin receptor and a C-terminal domain with a transmembrane motif. Mutants whose N-terminal or C-terminal domain was truncated were severely defective for sporulation. CONCLUSIONS: Meu10 is a spore wall component and plays a pivotal role in the formation of the mature spore wall structure.     

Functional combination of tapering profiles and overlapping arrangements in nonspanning skeletal muscle fibers terminating intrafascicularly

Using digital image analysis and several anatomical methods, morphometric analysis of nonspanning fibers which had tapering profiles at their intrafascicular termination sites and represented overlapping arrangements within the fiber fascicles was performed in the rat rectus abdominis. Special emphasis was focused on dimensional relationships occurring between overlapping portions and tapering segments and sarcomere lengths in non- and overlapping portions. Nonspanning fibers were found to overlap each other for more than 40% of their length. In length, their overlapping portions generally corresponded to their tapering segments, which were also greater than 40% of the fiber length. In addition, despite the presence of overlapping linkages, nonspanning fibers maintained a fairly uniform length irrespective of their overlapping and non-overlapping portions. Overlapping linkages in fibers without tapering profiles have a larger cross-sectional area in the overlapping portion than in the non-overlapping one, resulting in a phenomenon which will cause different sarcomere lengths between the two portions during fiber stretching. The present results suggest that tapering profiles in the overlapping portion ensure uniform sarcomere lengths within nonspanning fibers, thereby providing mechanical stability in each fiber. © 1993 Wiley-Liss, Inc.     

Copper and iron-induced oxidative damage in non-tumor bearing LEC rats

The copper and Iron status in the liver of non-tumor bearing Long-Evans Cinnamon (LEC) rats (average age 17 months) was investigated. A direct quantitation of loosely-bound copper and iron was also investigated by using a chelating agent, nitrilotriacetic acid (NTA-chelatable free copper and iron). Besides the total copper and iron contents, the level of NTA-chelatable free copper was also higher in LEC rats than In LEA rats (P<0.05). But for the free iron level there was no signiflcant difference between the two rat groups (P>0.05). The formation of thiobarbituric acid-reactive substances was higher In LEC rats than In LEA rats (P<0.01). The 4–hydroxy-2–nonenal (HNE)-modified proteins were also clearly demonstrated in LEC rat liver. The copper and iron which produced the most important effect In the process of oxidative damage in LEC rats could not be distinguished. Even though free copper, which could induce free radical injuries, was increased in LEC rats, neither tumor-induction nor preneo-plastic lesions in the experimental LEC rats were observed. Therefore it is speculated that the elevation of a free iron is another important factor. Copper and iron, both important translation metals In the body, may participate In the Induction of DNA damage and oncogenesls     

The adaptational strategies of the hindlimb muscles in the Tenrecidae species including the aquatic web-footed tenrec (Limnogale mergulus).

The hindlimb muscles in four species of Tenrecidae (Oryzoryctinae: Talazac long-tailed tenrec and web-footed tenrec, Tenrecinae: lesser hedgehog tenrec, and streaked tenrec), were examined macroscopically. The weight ratios of the muscles to the body in the oryzoryctinid species are larger than those in Tenrecinae, since the Oryzoryctinae species have an obviously smaller body from the evolutionary point of view. It can be primarily pointed out that the adaptation of the body size is different between the two subfamilies, and secondarily, that functional adaptation to locomotion is complete within each subfamily. The weight data and the morphological findings demonstrate that the web-footed tenrec possesses an extraordinary large M. semimembranosus in comparison to the Talazac long-tailed tenrec in their weight ratios. This muscle may act as a strong flexor motor in the knee joint during the aquatic locomotion of the web-footed tenrec. Since the other muscles of the web-footed tenrec are similar to those of the Talazac long-tailed tenrec regards weight ratio data, we think that the web-footed tenrec may have derived from a terrestrial ancestor such as the long-tailed tenrecs. In Tenrecinae the streaked tenrec is equipped with larger Mm. adductores, M. semimembranosus and M. triceps surae than the lesser hedgehog tenrec. This species is adapted to fossorial life derived from non-specialized ancestors within the evolutionary lines of the spiny tenrecs.     

Masked excitatory action of noradrenaline on rat islet β-cells via activation of phospholipase C

The effect of noradrenaline (NE) on rat islet -cells was examined. NE reduced insulin secretion from rat islets exposed to extracellular solutions containing glucose at 5.5 or 16.6 mM. In islets treated with pertussis toxin (PTX), however, NE increased insulin secretion. The NE-induced augmentation of insulin secretion was inhibited by prazosin. In intact islets, NE increased phospholipase C (PLC) activity, an effect that was prevented by treatment of islets with U-73122. NE elevated intracellular [Ca²⁺] ([Ca²⁺]_i) in isolated -cells independently of PTX. Although this NE effect was inhibited by prazosin, phenylephrine did not mimic it. The [Ca²⁺]_i response to NE was also prevented by the treatment of cells with U-73122. NE produced depolarization of -cells followed by nifedipine-sensitive action potentials. NE reduced the whole-cell membrane currents through ATP-sensitive K⁺ channels (K_ATP), responsible for the depolarization. This NE effect was prevented by treatment of -cells with U-73122 or BAPTA/AM. Although at least some of our results imply the presence of ₁-adrenoceptors, -cells were not stained by a polyclonal IgG antibody recognizing all adrenergic ₁-receptor subtypes so far identified. These results suggest that an interaction of NE with an unknown type of receptor activates rat islet -cells via a PLC-dependent signal pathway. This effect is, however, masked by the inhibitory action via a PTX-sensitive pathway also activated by NE.     

Essential role of rho kinase in the ca2+ Sensitization of Prostaglandin F2α-Induced Contraction of Rabbit Aortae

Although the prostate gland is a rich source of α1-adreno- (α1-AR) and m1-cholino receptors (m1-AChR), the membrane processes associated with their activation in glandular epithelial cells is poorly understood. We used the whole-cell patch-clamp technique to show that the agonists of the respective receptors, phenylephrine (PHE) and carbachol (CCh), activate cationic membrane currents in lymph node carcinoma of the prostate (LNCaP) human prostate cancer epithelial cells, which are not dependent on the filling status of intracellular IP₃-sensitive Ca²⁺ stores, but directly gated by diacylglycerol (DAG), as evidenced by the ability of its membrane permeable analogue, OAG, to mimic the effects of the agonists. The underlying cationic channels are characterized by the weak field-strength Eisenman IV permeability sequence for monovalent cations ( P _K(25) > P _Cs(4.6) > P _Li(1.4) > P _Na(1.0)), and the following permeability sequence for divalent cations: P _Ca(1.0) > P _Mg(0.74) > P _Ba(0.6) > P _Sr(0.36) > P _Mn(0.3). They are 4.3 times more permeable to Ca²⁺ than Na⁺ and more sensitive to the inhibitor 2-APB than SK&F 96365. RT-PCR analysis shows that DAG-gated members of the transient receptor potential (TRP) channel family, including TRPC1 and TRPC3, are present in LNCaP cells. We conclude that, in prostate cancer epithelial cells, α1-ARs and m1-AChRs are functionally coupled to Ca²⁺-permeable DAG-gated cationic channels, for which TRPC1 and TRPC3 are the most likely candidates.     

Transport of magnesium by two isoforms of the Na+-Ca2+ exchanger expressed in CCL39 fibroblasts

Cytoplasmic concentrations of Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) were measured with fluorescent indicators in CCL39 cells, a cell line established from Chinese hamster lung fibroblasts, transfected with complementary deoxyribonucleic acid (cDNA) of the Na+-Ca2+ exchanger isolated either from canine heart (NCX1) or from rat brain (NCX3). Raising extracellular [Mg2+] to 10 mM increased Mg2+ influx and the resultant change in [Mg2+]i (delta[Mg2+]i) was monitored with furaptra under Ca2+-free conditions. In control (vector-transfected) cells, delta[Mg2+]i at 45 min was similar with or without extracellular Na+ (130 mM or 0 mM) and when [Na+]i was raised by 1 mM ouabain treatment. delta[Mg2+]i in NCX1-transfected cells was attenuated significantly in the presence of 130 mM Na+, but became comparable to (or slightly larger than) that in control cells on either removal of extracellular Na+ or treatment with 1 mM ouabain. Cells expressing NCX3 showed an intermediate dependence of delta[Mg2+]i on Na+, probably reflecting a lower degree of expression of the exchanger protein. Extracellular Na+-dependent changes in [Ca2+]i (measured with fura-2 in the presence of extracellular Ca2+ and 10 microM ionomycin, a Ca2+ ionophore) were minimal in control cells, marked in the NCX1-transfected cells and intermediate in the NCX3-transfected cells. These results suggest that the Na+-Ca2+ exchanger (either NCX1 or NCX3) can transport Mg2+ and may play a role in the extrusion of magnesium from cells.