Determinants of Slow Walking Speed in Ambulatory Patients Undergoing Maintenance Hemodialysis

Walking ability is significantly lower in hemodialysis patients compared to healthy people. Decreased walking ability characterized by slow walking speed is associated with adverse clinical events, but determinants of decreased walking speed in hemodialysis patients are unknown. The purpose of this study was to identify factors associated with slow walking speed in ambulatory hemodialysis patients. Subjects were 122 outpatients (64 men, 58 women; mean age, 68 years) undergoing hemodialysis. Clinical characteristics including comorbidities, motor function (strength, flexibility, and balance), and maximum walking speed (MWS) were measured and compared across sex-specific tertiles of MWS. Univariate and multivariate logistic regression analyses were performed to examine whether clinical characteristics and motor function could discriminate between the lowest, middle, and highest tertiles of MWS. Significant and common factors that discriminated the lowest and highest tertiles of MWS from other categories were presence of cardiac disease (lowest: odds ratio [OR] = 3.33, 95% confidence interval [CI] = 1.26–8.83, P<0.05; highest: OR = 2.84, 95% CI = 1.18–6.84, P<0.05), leg strength (OR = 0.62, 95% CI = 0.40–0.95, P<0.05; OR = 0.57, 95% CI = 0.39–0.82, P<0.01), and standing balance (OR = 0.76, 95% CI = 0.63–0.92, P<0.01; OR = 0.81, 95% CI = 0.68–0.97, P<0.05). History of fracture (OR = 3.35, 95% CI = 1.08–10.38; P<0.05) was a significant factor only in the lowest tertile. Cardiac disease, history of fracture, decreased leg strength, and poor standing balance were independently associated with slow walking speed in ambulatory hemodialysis patients. These findings provide useful data for planning effective therapeutic regimens to prevent decreases in walking ability in ambulatory hemodialysis patients.     

Nonlethal G0-ts mutant tsJT60 becomes lethal at the nonpermissive temperature after transformation: a hint for new cancer chemotherapeutics

tsJT60 is a nonlethal temperature-sensitive (ts) mutant of a Fischer rat cell line (3Y1) classified as a G0 mutant; i.e., the ts defect is not expressed within the cell growth cycle but is expressed only between the G0 and S phase. tsJT60 clones transformed with oncogenes such as adenovirus E1A, polyoma large T, polyoma middle T, v-Ki-ras, and LTR activated c-myc, or with a chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine, grew well at 34 degrees C. However, most of these clones grew slowly at 40 degrees C, producing many floating dead cells, and some clones were killed at 40 degrees C. When they were cultured under conditions inadequate for growth of untransformed cells, such as high cell density or serum restriction, they were killed at 40 degrees C. These and previous results from SV40- and adenovirus-transformed tsJT60 clones favour the idea that transformed tsJT60 cells occasionally enter the G0 phase and are metabolically imbalanced at 40 degrees C during self-stimulation from the G0 to S phase. We propose that a drug which exclusively block, G0-G1 transition would be cytocidal to transformed cells but cytostatic to normal cells.     

Photoreduction of autooxidized albumin-heme hybrid in saline solution: revival of its O(2)-binding ability.

Recombinant human serum albumin (rHSA) incorporating 2-[8-[N-(2-methylimidazolyl)]octanoyloxymethyl]-5,10,15,20-tetrakis(alpha,alpha,alpha,alpha-o-pivalamido)phenylporphinatoiron(II)s (Fe(II)Ps) [rHSA-Fe(II)P] is a synthetic hemoprotein which can bind and release O(2) reversibly under physiological conditions (saline solution [NaCl]: 150 mM, pH 7.3) as do hemoglobin and myoglobin. However, the central ferrous ions of Fe(II)Ps are slowly oxidized to O(2)-inactive ferric forms. Based on the UV-vis. absorption spectroscopy, the majority of the autooxidized Fe(III)Ps in albumin are determined to be six-coordinate high-spin complexes with a proximal imidazole and a chloride anion, which show ligand-to-metal charge transfer (LMCT) absorption at 330 nm. Interestingly, photoirradiation of this LMCT band under an argon atmosphere led to reduction of the central ferric iron of Fe(III)P, allowing the revival of the O(2)-binding ability. The ratio of the photoreduction reached a maximum of 83%, which is probably due to the partial dissociation of the axial imidazole. The same photoirradiation under a CO atmosphere provides the corresponding carbonyl rHSA-Fe(II)P. Laser flash photolysis experiments revealed that the reduction was completed within 100 ns. The quantum yields (Phi) of these photoreductions were approximately 0.01.     

Dynamics of appearance and disappearance of the ripple structure in multilamellar liposomes of dipalmitoylphosphatidylcholine

The physical properties of the pretransition (P beta'----L beta') of dipalmitoylphosphatidylcholine liposomes were investigated using freeze-fracture electron microscopy. The kinetics of pretransition examined in the previous paper using TEMPO spin probe (Tsuchida, K., et al. (1985) Biochim. Biophys. Acta 812, 249-254) was extensively studied by observing the ripple structures in the freeze-fractured surfaces at different time intervals. When the temperature is decreased from 38 degrees C to 30 degrees C, the ripple structure disappears in the following steps. The intervals between ripples begin to expand with the decrease of ripple density upon the temperature shift, and this process continues for several tens minutes. Then, each ripple disappears gradually and changes into a completely smooth surface at 3 h after the temperature shift. The comparison of relaxation times between the previous ESR measurement and the present experiment suggests that the fast relaxation observed in the previous study corresponds to the expansion of the intervals between ripples. On the other hand, the ripple structure of regular intervals appears rapidly in some places and then spreads over the whole area of fractured surface when the temperature is increased from 23 degrees C to 35 degrees C. The results obtained in this work and the previous ESR work strongly suggest that the formation and disappearance of ripple structure is closely related to the relaxation processes near the pretransition temperature.     

Temporal behavioral variation and division of labor among workers in the primitively eusocial wasp,Polistes jadwigae Dalla Torre

The behavior of workers on 2 nests of the Japanese paper wasp,Polistes jadwigae, was recorded on video tape. Young workers performed pulp collection more frequently than middle-aged and old workers, while foraging of flesh (prey) was done mainly by middle-aged workers. Of the 26 behavioral categories, 7 showed negative, 2 concave, and 1 convex relationship to the workers age. Using behavioral profiles, workers could be classified into 3 age groups: 1) young workers (younger than 10 days old, active intranidal workers), 2) middle-aged workers (11–25 days old, extranidal workers) and 3) old workers (older than 26 days old, ‘idlers’). Idlers engaged in foraging and larval feeding significantly less frequency than the young and middle-aged workers, but they performed alerting toward many alien objects. Task specialization among workers irrespective of age polyethism was also suggested.     

The subunit structure of a major glutathione S-transferase form, MT, in rat testis. Evidence for a heterodimer consisting of subunits with different isoelectric points

A major glutathione S-transferase form (pI 5.7) in rat testis (MT) purified by S-hexyl-glutathione affinity chromatography, followed by chromatofocusing, showed two polypeptide of pI 6.7 (Yn1) and 6.0 (Yn2), having apparently the same molecular mass of 26 kDa on two-dimensional gel electrophoresis. Rechromatofocusing of the MT preparation after 4 M guanidine hydrochloride treatment revealed two additional protein peaks (pI 6.2 and 5.4). These were identified as the two homodimers consisting of the subunits of MT, Yn1Yn1 and Yn2Yn2, respectively. Furthermore, MT could be reconstituted from Yn1Yn1 and Yn2Yn2. These results indicate that MT is a heterodimer, Yn1Yn2, consisting of subunits with very similar molecular masses but different isoelectric points. The Yn1Yn1 form had glutathione S-transferase activities towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene. However, the Yn2Yn2 form had no activity towards any of the substrates examined. N-terminal amino acid sequences of subunits Yn1 and Yn2 revealed differences at two positions in the first 20 residues; the amino acid compositions of these subunits were also similar but not identical, indicating that these two subunits are different in the primary structure. Subunits Yn1 and Yn2 are immunologically related to each other and also to subunits 3 (Yb1) and 4 (Yb2) but they are not identical. These four subunits also showed a high degree of similarity in N-terminal amino acid sequences. Subunits Yn1 and Yn2 seem to belong to the rat GST 3-4 family or class mu. Subunits Yn1 and 4 can make a heterodimer, which is detectable not only in rat testis, but also in the heart, kidney and lung. The Yn1Yn1 form was not detected in the testis, but is present in rat brain [Tsuchida et al. (1987) Eur. J. Biochem. 170, 159-164]. The Yn2Yn2 form seemed to differ from GST 5-5 and may be a new form of rat glutathione S-transferase.     

Interactions of functionalized polymeric liposomes having a porphinato-iron complex with some biological cells and components in vitro

The hemocompatibility of functionalized polymeric liposome particles (diameter: 20-32 nm), which have a synthetic porphinato-iron complex in their polymerized bilayers and can carry oxygen, was studied in vitro. The ultramicroparticles did not induce hemolysis, platelet aggregation and plasma coagulation directly and were stable against hydrolysis by phospholipases A2 and D.     

Physical mapping of the virion and the prophage DNAs of a temperate Lactobacillus phage phi FSW

We analysed the physical structure of the DNA of phi FSW, which is a temperate phage of Lactobacillus casei S-1. A circular restriction map of the virion DNA has been constructed with three restriction endonucleases, BamHI, SalI and XhoI. Other data indicated that the phage genome was circularly permuted. In lysogens, the DNA of the prophage was found to be linearized at a specific site and integrated into a specific locus of the host genome, with the same orientation in each case, as evidenced by Southern filter hybridization. We compared the physical structure of phi FSW with its three virulent mutants. One of them had a restriction map indistinguishable from that of phi FSW and two of them contained host-derived DNA sequence(s) in a specific region of the phi FSW genome (V-region). The prophage integration site was mapped on a different segment of the phage genome to the V-region. Derivation of virulent mutants from phi FSW is discussed in relation to the physical structure of the phage genome.