Decrease of palmitoyl-CoA elongation in platelets and leukocytes in the patient of hereditary methemoglobinemia associated with mental retardation

Effect of the deficiency of NADH-cytochrome b5 reductase on fatty acid elongation was studied in the platelets and leukocytes taken from a patient of hereditary methemoglobinemia associated with mental retardation. The activity of fatty acid elongation was determined by measuring the incorporation of [2-14C]malonyl-CoA into palmitoyl-CoA. The de novo biosynthesis of fatty acids was blocked by the addition of phosphotransacetylase, and the elongation system could be assayed in the homogenates separated from de novo biosynthesis. As compared to normal subjects approximately 40% decrease of fatty acid elongation was observed both in the platelets and leukocytes from the patient.     

Taq I-generated HLA-DQ αpolymorphism in Japanese patients with narcolepsy

Taq I-generated HLA-DQrestriction fragment length polymorphism was examined in Japanese patients with narcolepsy. All patients were DR2 positive and shared a 6.0 kb fragment, although this fragment was found only in 54 % of the healthy DR2-positive Japanese. This finding added the DQ gene to the list of candidates for the possible narcolepsy-susceptibility gene. In contrast, there was no complete association between narcolepsy and DXrestriction fragment length polymorphism. These findings suggest that a narcolepsy-susceptibility gene is located closer to the DQ locus than to the DX locus.     

Morphological differentiation of endothelial cells co-cultured with astrocytes on type-I or type-IV collagen

Summary In this study bovine aortic endothelial cells were co-cultured with astrocytes from fetal Wistar Kyoto rats. Endothelial cells growing on type-I collagen, development. Although some cells appeared to be mature, horseradish peroxidase penetrated within 1 min of incubation through the intercellular junctions of these endothelial elements maintained on type-I collagen. In contrast, endothelial cells on type-IV collagen, co-cultured with astrocytes, were well developed; their intercellular junctions were well established, and plasmalemmal vesicles reduced in number. As a result, horseradish peroxidase was unable to penetrate through the endothelial cells grown on type-IV collagen and co-cultured with astrocytes because of the reduced extent of the junctional and vesicular transport. These findings reveal that (1) type-IV collagen is essential for the differentiation of endothelial cells, (2) endothelial cell-astrocyte interactions occur during co-culture, and (3) endothelial permeability depends on astrocyte-produced factors, in addition to type-IV collagen.     

Provocation of a paradoxical growth hormone response to corticotropin-releasing hormone by pretreatment with metoclopramide in patients with acromegaly and normal subjects

Two of 7 patients with acromegaly and one of 7 normal subjects exhibited a paradoxical rise in growth hormone (GH) to human corticotropin-releasing hormone (CRH) when pretreated with metoclopramide, although CRH alone did not induce an increase in GH. In one of these two patients with acromegaly, the GH increase to metoclopramide alone also reached the criteria of a paradoxical response. These two acromegalic patients showed a GH increase to metoclopramide pretreatment before and up to two months after surgery. In another acromegalic patient, whose GH level remained high 5 months after surgery, metoclopramide induced an increase in GH level, while in a patient who had an above-normal GH level 18 months after surgery, the resumption of physiological GH secretion after surgery was evidenced by a postoperative absence of a GH response to metoclopramide. It is suggested from these results that the GH response to metoclopramide and the metoclopramide-provoked GH response to CRH in patients with acromegaly result from the secretion of GH from nonadenomatous cells of the pituitary.     

Insulin and C-peptide secretion from B cells in human subjects stimulated with glucose

Two groups of immunoreactive insulin in human sera were reported by Kakita et al. (4), using gel chromatography after acid-alcohol extraction. These analogs were noted not only in circulating human sera but also in incubation medium and incubated human pancreas. The release of these insulin analogs was discussed in a previous report (5). The circulating C-peptide immunoreactivity was separated into two groups on a Bio-Gel column, and the early peak should not be proinsulin but an associated C peptide (6). These analogs of insulin were separated by the methods of ion-exchange chromatography, isoelectric focusing, gel electrophoresis, and gel chromatography. Immunoreactive insulin was also separated into two major bands by standard polyacrylamide gel electrophoresis. The fast migrating band corresponds to the rat insulin II position, and the slower corresponds to rat insulin I, which has one more basic amino acid residue in comparison with rat insulin II. Further studies have been performed in five healthy adults in order to elucidate the physiological relationship between analogs of insulin and C-peptide peak substances in human serum; the results are reported in this paper with a consideration of the mechanism of insulin secretion.     

Effects of different leaf traits on growth rates of insect herbivores on willows

We examined relative effects of traits of leaf quality of ten willow species (Salix: Salicaceae) on growth rates of five species of insect herbivores found in interior Alaska (a willow sawfly, Nematus calais; the tiger swallowtail butterfly, Papilio canadensis; and three species of chrysomelid beetles, Gonioctena occidentalis, Calligrapha verrucosa, and Chrysomela falsa). Leaf traits examined were water content, toughness, total nitrogen contnet, pubescence, and presence or absence of phenolic glycosides. Of ten Salix species, four species contain phenolic glycosides in their leaves. We examined relative effects of water content, toughness, and nitrogen content of the Salix leaves on larval growth rates at three different levels, i.e., on a single host species, between different host species, and between herbivore species. The within-host analyses showed that effects of water content, toughness and/or nitrogen content on herbivore growth rates were generally significant in early-season herbivores but not in late-season herbivores. For each herbivore species, differences in growth rates between hosts were not explained by differences in water content, toughness, or nitrogen content. The between-herbivore analysis showed that the interspecific difference in larval growth rates were related to difference in water and nitrogen content of the hosts. Pubescence of Salix leaves had little effects on herbivore growth rates. Presence of phenolic glycosides had a positive effects on growth rates of a specialist, N. calais, but no effect on the other specialist, Ch. falsa. Presence of phenolic glycosides had, in general, negative effects on growth rates of nonspecialists, G. occidentalis, C. verrucosa, and P. canadensis.     

Controlled release of adeno-associated virus from alginate hydrogel microbeads with enhanced sensitivity to ultrasound

Adeno-associated virus (AAV)-based gene therapy holds promise as a fundamental treatment for genetic disorders. For clinical applications, it is necessary to control AAV release timing to avoid an immune response to AAV. Here we propose an ultrasound (US)-triggered on-demand AAV release system using alginate hydrogel microbeads (AHMs) with a release enhancer. By using a centrifuge-based microdroplet shooting device, the AHMs encapsulating AAV with tungsten microparticles (W-MPs) are fabricated. Since W-MPs work as release enhancers, the AHMs have high sensitivity to the US with localized variation in acoustic impedance for improving the release of AAV. Furthermore, AHMs were coated with poly-l -lysine (PLL) to adjust the release of AAV. By applying US to the AAV encapsulating AHMs with W-MPs, the AAV was released on demand, and gene transfection to cells by AAV was confirmed without loss of AAV activity. This proposed US-triggered AAV release system expands methodological possibilities in gene therapy.     

Conformational changes in subdomain 2 of G-actin: fluorescence probing by dansyl ethylenediamine attached to Gln-41.

Gln-41 on G-actin was specifically labeled with a fluorescent probe, dansyl ethylenediamine (DED), via transglutaminase reaction to explore the conformational changes in subdomain 2 of actin. Replacement of Ca2+ with Mg2+ and ATP with ADP on G-actin produced large changes in the emission properties of DED. These substitutions resulted in blue shifts in the wavelength of maximum emission and increases in DED fluorescence. Excitation of labeled actin at 295 nm revealed energy transfer from tryptophans to DED. Structure considerations and Cu2+ quenching experiments suggested that Trp-79 and/or Trp-86 serves as energy donors to DED. Energy transfer from these residues to DED on Gln-41 increased with the replacement of Ca2+ with Mg2+ and ATP with ADP. Polymerization of Mg-G-actin with MgCl2 resulted in much smaller changes in DED fluorescence than divalent cation substitution. This suggests that the conformation of loop 38-52 on actin is primed for the polymerization reaction by the substitution of Ca2+ with Mg2+ on G-actin.     

Immunostimulatory activities of monoglycosylated α-d-pyranosylceramides

We compared the immunostimulatory effects of chemically synthesized α-galactosylceramides (α-GalCers), α-glucosylceramides (α-GluCers), 6″-monoglycosylated α-GalCer and 6″- or 4″-monoglycosylated α-GluCer and made the following observations: (1) the length of the fatty acid side chain in the ceramide portions greatly affects the immunostimulatory effects of α-GalCers and α-GluCers; (2) the configuration of the 4″-hydroxyl group of the inner pyranose moiety plays an important role in the immunostimulatory effects of monoglycosylated α- -pyranosylceramides; (3) the free 4″-hydroxyl group of the inner pyranose of monoglycosylated α- -pyranosylceramides plays a more important role in their immunostimulatory effects than the free 6″-hydroxyl group.     

Effect of Methionine Sulfoximine on Photosynthetic Carbon Metabolism in Wheat Leaves

Methionine sulfoximine (MSO) greatly reduced the carbon dioxideexchange rate (CER) of detached wheat (Triticum aestivvm L.cv Roland) leaves in 21% O₂, but only slightly reduced it in2% O₂. A supply of 50 mM NH₄Cl had little effect on the CERirrespective of the O₂ concentration. A simultaneous additionof glutamine and MSO protected against the inhibition of photosynthesisto a considerable extent and caused the accumulation of moreNH₃ than did the addition of MSO alone. Fixation of ¹⁴CO₂ in wheat leaves was inhibited by MSO treatmentin 22% O₂, and there was decreased incorporation of ¹⁴G intoamino acids and sugars and increased label into acid fractions.The addition of MSO and glutamine together eliminated the effectof MSO on the photosynthetic ¹⁴CO₂ fixation pattern. NH₄Cl stimulatedthe synthesis of amino acids from ¹⁴CO₂, especially the synthesisof serine in 22% O₂. Our observations show that factors other than the uncouplingof photophosphorylation by accumulated NH₃ may be responsiblefor the early stage of photosynthesis inhibition by MSO underphotorespiratory conditions. ¹Present address: Department of Agricultural Chemistry, KyushuUniversity, Fukuoka 812 Japan. ²Also at U.S. Department of Agriculture, Agricultural ResearchService, Urbana, Illionois 61801, U.S.A. (Received September 13, 1983; Accepted February 2, 1984)