Effect of immobilization on the ultrastructure of the golden hamster parathyroid gland

To investigate the morphological changes of the parathyroid gland of the immobilized hamsters, we studied the ultrastructure of the parathyroid gland of golden hamsters kept in special small cage (Ballman cage II). All hamsters of the control group were kept in one ordinary cage. Each hamster of the isolated group was kept in ordinary cage individually. Each hamster of the immobilized group was kept in Ballman cage II individually. All hamsters were kept for 5 days. On the first and fifth day of the experiment, bone mineral content (BMC) and bone mineral density (BMD) of whole body were measured by dual energy X-ray absorptiometry (DXA). In the control and isolated groups, BMD of the fifth day was significantly increased as compared to that of the first day. In the immobilized group BMC and body weight were significantly decreased. There was no significant difference among 3 groups concerning the mean serum calcium level. Volume density of the cell organelles and inclusions was estimated and compared among 3 groups. Volume density of the lysosomes and large vacuolar bodies of the isolated and immobilized groups was significantly higher than that of the control group. Much more lipid droplets were observed in the immobilized group than the control and isolated groups. No particular differences were observed as to the Golgi complex in the isolated and the immobilized groups compared to the control group. These findings suggest that the cellular activity of the parathyroid gland is suppressed with immobilization.     

Cloning and nucleotide sequencing of the genes, rpIU and rpmA, for ribosomal proteins L21 and L27 of Escherichia coli

The in situ content of cells of the reticuloendothelial system and lymphatic cells was examined in the skin of eight symptom-free HIV-positive individuals, three AIDS patients and eleven healthy immunocompetent volunteers. The epidermis was obtained in vivo by the suction blister technique. The numbers of CD68+, CD3+, CD8+, CD25-(IL2R)+ and HLA-DR+ intraepidermal cells proved to be independent of the number of CD4+ peripheral blood lymphocytes. At the same time, the intraepidermal concentrations of these cells were generally low in symptom-free HIV-infected individuals. The strong inverse correlation between the number of epidermal Langerhans cells (LC) and the severity of immunodeficiency was quantitatively confirmed; an increase in LC in symptom-free HIV-infected individuals was found. Thus, the reduction in these cells which was observed in the epidermis of AIDS patients began at a significantly elevated level. In contrast to results from other studies, in AIDS patients, in the present study, the concentration of epidermal LC did not differ significantly from that of healthy immunocompetent volunteers. The immunohistochemical technique can be as effective as in situ hybridization for the detection of HIV in the skin. Our results suggest that the viral load of the skin is rather low in HIV-infected subjects. HIV was demonstrated in one cell of one AIDS case by in situ techniques and this result was confirmed by a polymerase chain reaction examination using the same amount of tissue as for the in situ techniques.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synthesis of lactate (LA)-based poly(ester-urethane) using hydroxyl-terminated LA-based oligomers from a microbial secretion system

D-Lactate (LA)-based oligomers (D-LAOs), consisting of D-LA and D-3-hydroxybutyrate (D-3HB), are biobased compounds which are produced and spontaneously secreted by recombinant Escherichia coli. By supplementing the bacterial cultivation with diethylene glycol (DEG), the oligomers featuring hydroxyl groups at both ends of their structures, the D-LAOs-DEG, can be efficiently biosynthesized. In the present work, we attempted to verify the feasibility of D-LAOs-DEG as building blocks to be assembled into LA-based poly(ester-urethane) via polyaddition reaction with diisocyanate. The polymeric products were demonstrated by SEC and the urethane bound formation in the polymer was determined by FT-IR analysis, indicating that the polymerization was successfully performed. These results suggested that the one-step biosynthesized D-LAOs-DEG are potential substrates for the synthesis of LA-based poly(ester-urethane) and can be further applied to the synthesis of other LA copolymers.     

Improvement of strength and reliability of ceramics by shot peening and crack healing

In this study we propose a new method for improving the surface strength and reliability of ceramics that combines shot peening with crack-healing ability. We used Si₃N₄/SiC composite ceramics with high crack-healing ability and subjected the specimens to shot peening and crack healing. To evaluate the effect of our method, we investigated the residual stress after shot peening and crack healing and examined the specimens’ mechanical properties, including apparent fracture resistance, contact strength and bending strength. We found that shot peening and crack healing is effective to increase apparent fracture resistance, contact strength and bending strength.     

Preparation and characterization of end-alkoxysilylated polystrene and the grafting behaviors onto inorganic pigments. I. Utilization of 4-isopropoxydimethylsilyl-α-methylstyrene

Novel end-functional polystyrene having isopropoxydimethylsilyl (IPS) groups at the end part of the chain was prepared. IPS groups were introduced by the reaction between the living polystyryl anion and 4-isopropoxydimethylsilyl-α-methylstyrene ( 1 ) in THF at 195 K. The resultant polymer was characterized by GPC, ¹H-NMR, and TLC. It was confirmed that the polymer had several units of 1 at the chain end and a fairly narrow molecular weight distribution. IPS groups in the polymer can be hydrolyzed with strong acid such as mono-n-butylphosphate (MBP) but not with weak acid and base. Grafting behaviors of the polymer onto silica and alumina were studied in toluene in the presence of MBP as a catalyst. The polymer was grafted onto silica effectively. However, it cannot be grafted onto alumina because of predominant adsorption of MBP onto alumina having a basic surface. © 1995 John Wiley & Sons, Inc.     

Low-temperature methanol synthesis from carbon dioxide and hydrogen via formic ester

A new route of methanol synthesis, at 443 K and under pressurized conditions, from carbon dioxide and hydrogen through formic ester was investigated, by using Cu-based catalysts. This one-pot reaction consisted of three steps:

1. formic acid synthesis from CO₂ and H₂,

2. esterification of formic acid by ethanol to ethyl formate, and

3. hydrogenolysis of ethyl formate to methanol and ethanol.

Donor–Acceptor Poly(3‐hexylthiophene)‐block‐Pendent Poly(isoindigo) with Dual Roles of Charge Transporting and Storage Layer for High‐Performance Transistor‐Type Memory Applications

Field‐effect transistor memories usually require one additional charge storage layer between the gate contact and organic semiconductor channel. To avoid such complication, new donor–acceptor rod–coil diblock copolymers (P3HT₄₄‐b‐Piso_n) of poly(3‐hexylthiophene) (P3HT)‐block‐poly(pendent isoindigo) (Piso) are designed, which exhibit high performance transistor memory characteristics without additional charge storage layer. The P3HT and Piso blocks are acted as the charge transporting and storage elements, respectively. The prepared P3HT₄₄‐b‐Piso_n can be self‐assembled into fibrillar‐like nanostructures after the thermal annealing process, confirmed by atomic force microscopy and grazing‐incidence X‐ray diffraction. The lowest‐unoccupied molecular orbital levels of the studied polymers are significantly lowered as the block length of Piso increases, leading to a stronger electron affinity as well as charge storage capability. The field‐effect transistors (FETs) fabricated from P3HT₄₄‐b‐Piso_n possess p‐type mobilities up to 4.56 × 10^?2 cm² V^?1 s^?1, similar to that of the regioregular P3HT. More interestingly, the FET memory devices fabricated from P3HT₄₄‐b‐Piso_n exhibit a memory window ranging from 26 to 79 V by manipulating the block length of Piso, and showed stable long‐term data endurance. The results suggest that the FET characteristics and data storage capability can be effectively tuned simultaneously through donor/acceptor ratio and thin film morphology in the block copolymer system.     

Atrial natriuretic peptide inhibits endothelin-1-induced activation of JNK in glomerular mesangial cells

Atrial natriuretic peptide (ANP) has been shown to counteract various actions of endothelin-1 (ET-1) in mesangial cells. We have reported that both extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) are activated by ET-1 and ET-1-induced activation of ERK is inhibited by ANP. To further clarify the action of ANP, we examined the effect of ANP on ET-1-induced activation of JNK. ANP inhibited ET-1-induced activation of JNK in a dose-dependent manner. This inhibitory effect of ANP was reversed by HS-142-1, an antagonist for biological receptors of ANP, while C-ANP, an analog specific to clearance receptors of ANP, failed to inhibit ET-1-induced activation of JNK. 8-Bromo-cGMP and sodium nitroprusside were also able to inhibit ET-1-induced activation of JNK, suggesting cGMP-dependent action of ANP. In contrast, ANP failed to inhibit interleukin-1 beta (IL-1 beta)-induced activation of JNK. Since an increase in intracellular calcium ([Ca2+]i) was shown to be necessary for ET-1-induced activation of JNK in mesangial cells, we measured [Ca2+]i using fura-2. ANP attenuated the ET-1-induced increase in [Ca2+]i in concentrations enough to inhibit ET-1-induced activation of JNK. Finally, ANP was able to inhibit ET-1-, but not IL-1 beta-induced increase in DNA-binding activity of AP-1 by gel shift assay. These results indicate that ANP is able to inhibit ET-1-induced activation of AP-1 by inhibiting both ERK and JNK, suggesting that ANP might be able to counteract the expression of AP-1-dependent genes induced by ET-1.