Effects of anticipation, prior-exercise, and breathing frequency to ventilatory response during step exercise: a preliminary study.

We examined the effects of anticipation, prior-exercise, and restricted breathing frequency on the ventilatory transient response to bicycle step exercise (75 W, 4 min, 50 rpm), i.e., 1) whether the increase of work rate was anticipated by the subject or not, 2) whether the exercise was preceded by light exercise (25 W), or rest, and 3) whether the exercise entrained the breathing frequency (f: 12.5/min, or 25/min) or not (voluntary). The corresponding step-on exercise was randomly performed at least two to five times by one adult male subject. As a result, a) the initial rapid ventilatory component, phase 1, was not observed when initiated from light exercise, whereas the overshot phase 1 was observed from rest in anticipation and voluntary breathing frequency condition due to the rapid increase of tidal volume; b) compared with the anticipation condition, the phase 1 response of VE in the non-anticipation condition was slower with prior-rest, and not with prior-light exercise; and c) the restriction of the breathing frequency for entraining the exercise rhythm did not affect the initial rapid response, but decreased the fluctuation of VE in the steady state, compared to the condition of voluntary breathing frequency.     

Effects of food deprivation and high fat diet on immunoreactive dynorphin A(1–8) levels in brain regions of Zucker rats

The levels of immunoreactive dynorphin A(1–8) (ir-DYN8) were measured in discrete brain regions of lean Zucker rats subjected to food deprivation for 72 hr and to a high fat diet, and in fatty Zucker rats after food deprivation for 72 hr. Fatty rats showed higher concentrations of ir-DYN8 in the cortex and midbrain, when compared to lean rats fed a stock diet ad lib. Food deprivation increased ir-DYN8 levels in the cortex of lean rats and fatty rats and in the hippocampus of fatty rats, but decreased its content in the striatum of lean rats and in the midbrain of fatty rats. The high fat diet increased ir-DYN8 levels in the cortex and midbrain of lean rats. These results suggest that ir-DYN8 levels in extrahypothalamic structures of Zucker rats could be differentially modified under conditions of hereditary obesity and dietary manipulations.     

Proton magnetic resonance spectra of D-gluco-oligosaccharides and D-glucans

The p.m.r. spectra of some D-gluco-oligosaccharides and D-glucans in deuterium oxide were studied with respect to the anomeric proton. In (1→2)-linked glucobioses, the effect of change in configuration of the hydroxyl group at C-1 on the chemical shifts of the glycosidic proton is noted. Equilibrium mixtures of (1→2)-linked glucobioses contained more α-anomer than did the other examples, despite the cis configuration of substituents at C-1 and C-2. Some D-glucans were investigated with regard to the degree of branching, although solubility was a limitation.     

G2 arrest of cell cycle ensures a determination process of sensory mother cell formation in Drosophila

 In Drosophila, the sensory mother cells of macrochaetes are chosen from among the mitotically quiescent clusters of cells in wing imaginal discs, where other cells are proliferating. The pattern of cyclin A, one of the G2 cyclins, reveals that mitotically quiescent clusters of cells are arrested in G2. When precocious mitoses are induced during sensory mother cell determination by the ectopic expression of string, a known G2/M transition regulator, the formation of sensory mother cells is disturbed, resulting in the loss of macrochaetes in the adult notum. This suggests that G2 arrest of the cell cycle ensures the proper determination of sensory mother cells. Received: 16 December 1996 / Accepted: 14 March 1997     

Enzymatic synthesis of β-D-Gal-(1→3)-[β-D-GlcNAc-(1→6)]-α-D-GalNAc-OC6H4NO2-p as a carbohydrate unit of mucin-type 2 core

We have established a synthetic method for obtaining β-D-Gal-(1→3)-[β-D-GlcNAc-(1→6)]-α-D-GalNAc-OC6H4NO2 -p (1), which is a carbohydrate unit of mucin-type 2 core. A β-N-acetyl-D-hexosaminidase from Nocardia orientalis catalyzed the synthesis of the desired compound 1 with its isomers β-D-GalNAc-(1→6)-β-D-Gal-(1→3)-α-D-GalNAc-OC6H4NO2-p (2) β-D-GlcNAc-(1→3)-β-D-Glc-(1→3)-α-D-GalNAc-OC6H4NO2-p (3) through N-acetylglucosaminyl transfer from N,N′-diacetylchitobiose and β-D-Gal-(1→3)-α-D-GalNAc-OC6H4NO2-p. The enzyme formed the trisaccharides 1, 2, and 3 in 14% overall yield based on β-D-Gal-(1→3)-α-D-GalNAc-OC6H4NO2-p as an acceptor substrate, and in the ratio of 44:32:24. In this way, N-acetylglucosaminyl transfer favored O-6 of the acceptor rather than O-6′, and occurred to a lesser extent at O-3′. This reaction was efficient enough to allow a one-pot preparation of the desired carbohydrate unit of mucin-type 2 core. When β-D-Gal-(1→3)-β-D-GalNAc-OC6H4NO2-p was used as an acceptor, the enzyme also synthesized three kinds of trisaccharides in the same regioselectivity with respect to O-6 and O-6′ versus O-3′ of the acceptor.     

Intracellular localization of Staphylococcus aureus within primary cultured mouse kidney cells.

Staphylococcus aureus Cowan I was incubated with monolayers of cells derived from several portions of mouse kidney, and found to be ingested by all types of the renal cells. Intracellular localization of S. aureus was determined by resistance of intracellular cocci against lysostaphin digestion and confirmed by electron microscopy. From renal medulla, three morphological variants of the hyperosmolarity-tolerant (HOT) cells were obtained. The rate of cocci-ingesting cells varied from 16.9% to 93.4% among these of the HOT cells at the end of 3-hr incubation. From renal cortex, three morphological variants of epithelial cells grew in medium RK-1. Among them, only the cells on the edge of colony ingested Cowan I, while the epithelial cells on the center of colony ingested few cocci. Transferred from medium RK-1 to MEM supplemented with 10% FBS, part of the cortical cells changed into fibroblast-like appearance and obtained the capacity to ingest Cowan I. This result may indicate the correlation between ingesting capacity and cellular morphology. From a glomerulus, epithelial (GE) cells and fibroblast-like (GF) cells were obtained. The GE cells ingested not only S. aureus Cowan I but Staphylococcus epidermidis and Staphylococcus saprophyticus after 30-min incubation, while the GF cells, like both of the HOT cells and the cortical cells, ingested only S. aureus. These results suggest a possibility that S. aureus is located within nonprofessional phagocytes during its infection and intracellular coccus plays an important role in its pathogenicity.     

Platelet aggregation by strains of enterococci.

The platelet aggregation capability of whole cells of Enterococcus faecalis, E. faecium and E. avium was tested. The optimum ratios of bacteria to platelets in E. faecalis (strain SMU-37), E. faecium (strain SMU-138) and E. avium (strain SMU-197) were 1.0, 1.2 and 2.0, respectively. During the platelet aggregation induced by the three strains of enterococci, 65-69% of total serotonin was released. The aggregation was totally inhibited by ethylenediaminetetraacetate (10 mM) and apyrase (1 mg/ml), while no effect was shown by aspirin (10 mM), indomethacin (10 mM) and quinacrine (1 mM). By pretreatment of platelet-poor plasma with heat (56 C, 30 min) or zymosan, the reactivities with platelets of each strain of species were markedly diminished. These results suggest that enterococci-induced platelet aggregation was an ion-dependent, cyclooxygenase-insensitive event, and plasma component(s) was (were) required for the reaction.