Study of insulin response to oral glucose load after acute and chronic glycemic control in type 2 diabetic subjects

To investigate whether correction of fasting hyperglycemia per se improves the insulin secretion in type 2 diabetic subjects, plasma insulin response to 75 g oral glucose load has been studied after acute and chronic normalization of fasting plasma glucose levels in 7 overt type 2 diabetic subjects. For the acute normalization of elevated fasting plasma glucose levels, an artificial endocrine pancreas was employed. Although fasting plasma glucose concentrations were normalized before the oral glucose challenge, insulin response to oral glucose was not improved compared to those without normalization of fasting plasma glucose levels. After 1-3 month control of hyperglycemia, the insulin response to glucose in the subjects was significantly improved compared to those without treatments. Results indicate that chronic metabolic control is essential for the improvement of insulin response to glucose in type 2 diabetic subjects, and also suggest that the impaired insulin secretion in type 2 diabetes is not due to hyperglycemia per se, but due to the metabolic derangements which lead to chronic hyperglycemia.     

Early development of the laboratory-reared flounder,Pleuronichthys cornutus

Fertilized eggs ofPleuronichthys cornutus were obtained by both artificial fertilization and natural spawning of laboratory-reared fish. The present paper describes in detail the early development of the fish and the rearing methods employed to provide basic information for mass production of this species. Eggs and sperm for artificial fertilization were obtained from adult fish caught in the Ariake Sound, Kyushu in November and December of 1984. Their maturation was successfully induced by intermuscular injection of pituitary homogenate of the silver carp,Hypophthalmichthys molitrix. Fertilized eggs were also obtained in 1985 by natural spawning of a broodstock kept in a tank for a year. Hatched larvae were fed successively with rotifers,Artemia nauplii and the harpacticoid copepod,Tigriopus japonicus and reared for 80 days. Ten thousand young fish of about 33 mm TL were obtained in 1984 and 1985 with the survival rate of about 17%. Ten developmental stages were defined on the basis of the morphological characteristics: A) newly hatched to 4 day old larvae, 2.7 to 4.1 mm TL (2.6 to 3.9 mmNL), yolk sac present; B) 4 to 16 day old larvae, 3.8 to 5.9 mm (3.6 to 5.6 mm), yolk resorbed, actively feeding on rotifers; C) 15 to 30 day old larvae, 6.3 to 8.3 mm (6.0 to 7.9 mm), notochord straight, hypural fin ray visible; D) 24 to 40 day old larvae, 6.7 to 9.2 mm (6.4 to 8.8 mm), caudal notochord upturned (45°); E) 28 to 45 day old larvae, 7.9 to 10.8 mm (7.5 to 10.3 mm), caudal notochord upturned (45°–90°); F) 32 to 50 day old larvae, 10.8 to 15.7 mm (8.8 to 12.8 mm BL), eyes symmetrical; G) 35 to 66 day old larvae, 13.4 to 20.0 mm (10.9 to 16.3 mm), eyes asymmetrical, but left eye not visible from the right side; H) 40 to 75 day old larvae, 13.8 to 26.2 mm (11.3 to 21.4 mm), the upper edge of left eye visible over top of the head from the right side; I) 46 to 89 day old larvae, 20.1 to 27.4 mm (16.4 to 22.4mm), left eye on the edge of the head and pupil visible from the right side; and J) juveniles of 51 day old or over, 23.6 mm or more (19.3 mm or more), metamorphosis completed. One to three inflections were found for relative growth of total length, eye diameter, upper jaw length, preanal length, and distance between the base of the pectoral fin and the anus against the notochord length or body length. Two inflections were found for body length (or notochord length)-body weight relationship. Most inflections appeared at the stages of D, F and J, corresponding to the body length of 8, 9–12 and 18–22 mm respectively.     

Effects of monoenergetic X-rays with resonance energy of bromine K-absorption edge on bromouracil-labelled E. coli cells

In order to examine enhanced killing that might be induced by Auger cascades in the incorporated atoms in cells, bromouracil(BrU)-labelled E. coli cells were irradiated with monoenergetic X-rays at 13.49 and 12.40keV, just above and below the K-absorption edge of bromine. In both cases BrU-labelled cells were more sensitive for killing than were normal cells. However, when the degree of BrU-sensitization was compared between the two energies of X-rays, the enhanced killing at 13.49 keV was only small, 2 +/- 8 per cent based on the D0 value in saline. By the addition of DMSO, which is believed to suppress radical-mediated effects, killing of BrU-labelled cells was enhanced at 13.49 keV by 8 +/- 4 per cent as compared with 12.40 keV, based on D0. These results have been examined in terms of absorbed energy in BrU-labelled cells and in terms of the number of induced Auger events.     

Induction of ovarian maturation and development of eggs,larvae and juveniles of the tonguefish,Cynoglossus abbreviates,reared in the laboratory

Cynoglossus abbreviatus spawns from mid-March to mid-April in the Sea of Shimabara in Kyushu. During the spawning season ovarian maturation was successfully induced by injection of the pituitary homogenate ofHypophthalmichthys molitrix. The dose of the aceton-dried pituitary homogenate was 6.5 mg/kg body weight ofC. abbreviatus. It took about 2 days for ovulation after injection at a water temperature of 14 to 16°C. Artificial fertilizations were accomplished on March 29, 1974 and again on April 7, 1984, using the females matured by hormone injection in the latter case only. The larvae were reared on the rotifers,Artemia nauplii,Tigriopus japonicus and copepods collected from the sea over a period of 113 days in 1974 and 58 days in 1984. The eggs were pelagic, spherical, 1.19–1.23 mm in diameter and had 30–50 oilglobules of 0.068–0.095 mm in diameter, and the perivitelline space was narrow. The incubation period was 90–98 hours at a water temperature of 14 to 16°C. The newly hatched larvae were 3.18–3.45 mm TL and had 61–64 myomeres. The larvae had many melanophores and xanthophores on the body, forming three bands on the caudal region, but were lacking chromatophores on the finfolds. The yolk was completely absorbed when the larvae attained a size of 4.7–5.6 mm TL 8 days after hatching. A single elongated dosai fin ray developed on the head in the 8-day old larvae. The ray was reduced in size as long as the other rays 1 or 2 days after metamorphosis. The rudiment of pectoral fins were found on the both sides of the body in the 2-day old larvae, but two of them disappeared after metamorphosis. A pelvic fin first appeared as a ventral bud just anterior to the gut in the larva of 8.39 mm TL. The full count of 4 rays was observed on the larva of 10.83 mm TL. Metamorphosis began 22 days after hatching when the larvae were 11.20 mm TL. The right eye began to shift the left side of the head at night and reached to the final place after 8.5 hours. It took about 36 hours to complete the metamorphosis, including the eye movement and fusion of the hole in the rostral beak. At the last stage of metamorphosis, the dosal, caudal, anal and ventral fins became confluent. The larvae reached the juvenile stage at a size of 13.5–14.0 mm TL, approximately 28 days after hatchling. The growth of larvae reared in 1974 is expressed by the following equations: Y₁ = 3.448 · 1.0507^x (8≦X≦28) Y₂ = 6.3322 · 1.0275^x (28≦X≦75) where Y is the total length (mm) and X is the number of days after hatching. Growth rate changed after metamorphosis.     

Transformation of L cells with virus thymidine kinase genes introduced by red cell-mediated microinjection

Fusion of red cell ghosts containing foreign materials with cells results in the introduction of the materials into the cells (red cell-mediated microinjection). Until now, 'two-step dialysis' has mainly been used for trapping proteins in the ghosts. Large-sized materials such as DNA, however, are rarely trapped in the ghosts, since the holes in the red cell membrane caused by osmotic shock are too small for such materials to pass through. In this study, we improved the trapping technique. Some of the Hind III fragments of lambda phage DNA as well as proteins could be trapped in the ghosts when the mixture of these materials and red cells were frozen at -80 degrees C for a short period followed by quick thawing. Red cell-mediated microinjection using ghosts containing plasmid pBR322 linked with a Herpes simplex viral thymidine kinase (tk) gene brought about transformation of tk-defective L cells, the efficiency of transformation was 1 out of 20 000-60 000 cells fused with the ghosts.     

Effects of serine protease inhibitors on oxyradical burst from phagocytizing neutrophils—analysis by chemiluminescence counting and its microscopic imaging

Reaction difference of oxyradical generation and luminol-dependent photoemission of zymosan- and phorbol ester-treated neutrophils were investigated using a conventional photomultiplier and ultrasensitive photonic imaging technique. Zymosan-treated cells released a concentrated photonic burst corresponding to the cellular distribution. In contrast, phorbol ester-treated cells produced a negligible level of photoemission, and the additional application of Ca²⁺ ionophore enhanced the photonic burst, which was gradually spread out into extracellular space. Serine protease inhibitors did not attenuate PMA-induced chemiluminescence but did attenuate zymosan-induced chemiluminescence. This suggests the involvement of serine protease in the respiratory burst of phagocytizing neutrophils.     

A temperature-sensitive osmophilic mutant of Zygosaccharomyces rouxii

Summary A temperature-sensitive osmophilic mutant of Zygosaccharomyces rouxii, OS15, was isolated, which required high salt or sugar concentration for growth above 30°C. Cell viability at 35°C in the presence of NaCl was higher than in the absence of NaCl, and a survival ratio of the mutant cells after incubation at 55°C was also higher in the presence of NaCl than NaCl-free condition. Furthermore, resistance to UV light, hygromycin B and geneticin was improved in the presence of NaCl. There was no difference between the parent and the mutant in fatty acid saturation and microscopic cell shape under NaCl condition.     

Genetic Mapping of Four Mouse bHLH Genes Related toDrosophilaProneural Geneatonal

It has been shown that mammalian neurogenesis is partly controlled by multiple basic helix–loop–helix (bHLH) genes, as inDrosophila.Recently, mouse homologs ofDrosophila atonal,a proneural gene encoding a bHLH protein required for chordotonal organ and photoreceptor development, have been characterized to obtain further insights into the molecular nature of mammalian neurogenesis. Here, to assess their potential involvement in genetic neural disorders, we have determined genetic map positions for four mouseatonal-related genes,Atoh1, Atoh2, Atoh3,andNdrf,which encode MATH-1, MATH-2, MATH-3, and NDRF, respectively. Interspecific backcross analysis indicated thatAtoh1andAtoh2were located in separate positions of Chr 6 and thatAtoh3andNdrfwere mapped to Chr 10 and Chr 11, respectively. Thus, these structurally related genes are located separately on multiple chromosomes.