Acute effects of distribution of rest between repetitions.

The purpose of this study was to compare acute mechanical and metabolic effects of 2 sessions of resistance training equated by volume and total resting time but with different set configuration: sets to failure (FS) vs. distribution of rest between each repetition (NFS). 10 male judoists completed a session consisting of 3 sets to failure of parallel back squat with 4 repetitions at maximum load, and a rest of 3 min between the sets. At least 72 h later subjects developed the same volume, but total resting time was distributed among individual repetitions. Before and after sessions isometric force and mean propulsive velocity with load corresponding to maximum propulsive power were assessed. Results showed that in respect to FS, NFS showed an 18.94% (± 17.98) higher average mean propulsive velocity during session (0.42 ± 0.04 vs. 0.35 ± 0.08 m.s - 1; p=0.009), lower blood lactate concentration after session (maximum average value 1.52 ± 0.77 vs. 3.95 ± 1.82; session effect: p=0.001) and higher mean propulsive velocity with load corresponding to maximum propulsive power (mean propulsive velocity immediately after session 0.64 ± 0.09 vs. 0.59 ± 0.12 m.s - 1; session effect: p=0.019). These data show that distribution of rest in sessions equated for volume and total resting time determines differences in performance during sessions and mechanical or metabolic acute effects.

Long-term radiographic appearance of a bioabsorbable biocomposite tibial tuberosity advancement cage implant.

OBJECTIVE: To report the radiographic appearance of a bioabsorbable biocomposite tibial tuberosity advancement cage at least 1 year after implantation. Design Retrospective case series. METHODS: Medical records (February 2014-March 2015) of dogs receiving a biocomposite tibial tuberosity advancement cage were reviewed. Cases were selected if they had undergone surgery at least 1 year before the selection, no additional surgeries were performed, and no known surgical site infection had occurred. Medical record information assessed included signalment, body weight (kg), affected stifle joint (left or right), date of original surgery and the size of biocomposite cage used (9 or 12 mm). Radiographs were evaluated by two blinded radiologists who calculated percentages of osteolucency present in five zones around the cage and assigned a numerical score based on these calculations. Variables were evaluated statistically for effect on lucency percentage and numerical score. RESULTS: Fifty dogs were included. Zone 5 (caudoproximal area) was found to have the lowest lucency percentage and score and zone 3 (distal area) had the highest lucency percentage and score. Twelve-millimetre cages were significantly associated with a higher lucency numerical score than 9 mm cages. CONCLUSION: A biocomposite tibial tuberosity advancement cage was found to have variable amounts of radiographically apparent osseous integration at least 1 year after implantation.

The discovery of a potent Nav1.3 inhibitor with good oral pharmacokinetics.

In this article, we describe the discovery of an aryl ether series of potent and selective Nav1.3 inhibitors. Based on structural analogy to a similar series of compounds we have previously shown bind to the domain IV voltage sensor region of Nav channels, we propose this series binds in the same location. We describe the development of this series from a published starting point, highlighting key selectivity and potency data, and several studies designed to validate Nav1.3 as a target for pain.

Lymphocyte plasma membranes. VI. Surface antigens of lymphocytes in chronic lymphocytic leukemia.

Surface antigens from lymphocytes of patients with chronic lymphocytic leukemia (CLL) and from normal peripheral blood lymphocytes (PBL) were examined by radioimmunoassay; antisera to lymphocytes (ALS) were used to bind the labeled antigens. Cells from patients with CLL, normal PBL, thymus cells (THY), and cultured human lymphoblasts (CHL) were labeled by lactoperoxidase-catalyzed iodination. ALS (prepared against THY and CHL) were used to bind the labeled antigens solubilized in nonionic detergent. PBL resembled THY, but the CLL resembled CHL. Thus ALS(CHL) had greater potency for CLL antigens than for PBL antigens when compared to ALS(THY). Furthermore, the electrophoretic profiles of the immunoprecipitates from CLL cells revealed a peak of approximately 30,000-35,000 mol wt, which was not found for PBL or THY, but was associated with CHL.

Changes in NAD levels in human lymphocytes and fibroblasts during aging and in premature aging syndromes.

NAD levels markedly increase upon mitogen stimulation of lymphocytes from young subjects. In contrast, lymphocytes from old subjects do not increase NAD levels upon stimulation. A survey of 35 individuals aged 18-79 years revealed a significant age-dependent decrease in the NAD response to mitogen stimulation. No significant differences were noted in lymphocytes from age-matched individuals with Down's syndrome or diabetes mellitus. On the other hand, cultured skin fibroblasts showed elevated NAD levels with age. However, this effect appears to be due to increased size of the cells since the NAD/protein ratio is unchanged. Skin fibroblasts from patients with progeria exhibit much higher levels of NAD and protein per cell than age-matched controls.

Impaired glycolysis of human lymphocytes during aging.

When peripheral lymphocytes from young persons are stimulated in vitro with phytohemagglutinin, an increase in the levels of all the glycolytic enzymes occurs concomitantly with blastogenesis. The specific activities of enzymes increase approximately 200%, with a greater induction of the latter half of the pathway. The increases do not represent a general enzyme induction, since nonglycolytic enzymes such as glucose 6-phosphate dehydrogenase and isocitrate dehydrogenase do not increase during transformation. Human lymphocytes from a geriatric population were also subjected to mitogen stimulation under identical conditions. The initial levels of the enzymes were essentially identical in lymphocytes from young and old subjects as were cultured controls which received no mitogen. However, during mitogen stimulation the cells from the old subjects failed to increase the glycolytic enzymes. This inability to activate glycolysis may be related to the decline in cell-mediated immunity which is known to occur with advancing age.

Fractionation on lymphocyte surface antigens. I. Rapid method for eliminating labeled lipid from cell surface antigens iodinated by the lactoperoxidase catalysed reaction.

Fractionation of lactoperoxidase iodinated cell surface material on miniature DEAE-cellulose columns provided a rapid method for separating labeled lipid from cell surface antigens. The procedure also removed poorly solubilized aggregates yielding a labeled preparation which demonstrated stable, reproducible immunoprecipitation results. Using these fractionated antigens components tentatively designated as human 'T' cell specific antigens have been identified.

Comparison of in vivo cholinesterase inhibition in neonatal and adult rats by three organophosphorothioate insecticides.

Developing mammals are more sensitive than adults to a variety of organophosphorothioate insecticides (OPs), compounds which act in vivo by inhibition of cholinesterase (ChE). Little is known, however, regarding age-related differences in biochemical responses to these toxicants. The time course of ChE inhibition and recovery in whole brain was compared in neonatal (7 days of age) and adult (80-100 days of age) rats after treatment with maximal tolerated doses (MTDs) of either methyl parathion (MPS), parathion (PS) or chlorpyrifos (CPF). Neonatal rats were more sensitive than adults in all cases (MTDs for MPS, PS and CPF; neonates = 7.8, 2.1 and 45 mg/kg, s.c.; adults = 18, 18, and 279 mg/kg, s.c., respectively). In general, maximal brain ChE inhibition was similar (greater than 78%) in both age groups but ChE activity recovered faster in neonates. Plasma and erythrocyte ChE activities correlated relatively well (r = 0.794-0.943) with brain ChE activity in neonatal rats at all time points between 4 h and 7 days after treatment but similar correlations between circulating and brain ChE activities in adults were more variable (r = 0.211-0.917). The results indicate that neonatal rats are more sensitive to acute lethality from these compounds and that MTD exposures produce extensive brain ChE inhibition in both age groups. Significant inhibitor-related and age-related differences in the duration of ChE inhibition can ensue, however, following such OP exposures.

Phenylmethylsulfonyl fluoride alters sensitivity to organophosphorus-induced delayed neurotoxicity in developing animals.

The serine/cysteine hydrolase inhibitor phenylmethylsulfonyl fluoride (PMSF) markedly intensifies the clinical expression of organophosphorus-induced delayed neurotoxicity (OPIDN) in adult chickens when administered after organophosphate exposure. In this study, we have examined the ability of PMSF post-treatment to affect sensitivity to OPIDN in developing animals at ages normally showing resistance. Chickens (35, 49 or 70 days of age) were treated with diisopropylphosphorofluoridate (DFP, 2 mg/kg, sc) and then treated four hours later with PMSF (90 mg/kg, sc) or vehicle only and examined for clinical signs of ataxia and incoordination. Chickens treated with DFP alone showed a marked age-related increase in the severity of motor deficits. Birds treated with DFP followed by PMSF showed more extensive clinical deficits relative to those treated with DFP only, but relatively similar degrees of motor dysfunction among the age groups. Cervical spinal cord samples processed by the Fink-Heimer degeneration method indicated that PMSF post-treatment induced more extensive axonal degeneration in all age groups relative to treatment with DFP only. As the DFP treatment alone caused greater than or equal to 90% inhibition of neurotoxic esterase activity (NTE, the putative molecular target site for OPIDN), interaction with NTE by PMSF does not appear to be involved in potentiation. We hypothesize that PMSF potentiates OPIDN through impairment of a physiological process which normally imparts resistance to young animals and which regresses during development.

Long-term neurochemical and behavioral effects induced by acute chlorpyrifos treatment.

A single dose of the organophosphate insecticide O,O'-diethyl-O-3,5,6- trichloro-2-pyridylphosphorothioate [chlorpyrifos (CPF), 279 mg/kg, SC] caused extensive inhibition of cortical and striatal cholinesterase (ChE) activity in adult rats at 2 (94-96%), 4 (82-83%), and 6 (58-60%) weeks after treatment. These persistent changes in ChE activity were concomitant with reductions in muscarinic receptor binding sites in cortex (34, 33, and 18% reduction in Bmax) and striatum (48, 40, and 23% reduction in Bmax) at 2, 4, and 6 weeks after exposure. Neither ChE activities nor muscarinic receptor densities were different from control levels at 12 weeks after exposure. CPF treatment caused a reduction in locomotor activity for the first 2 days after treatment, after which basal activity levels were not different from controls. CPF-treated rats showed higher activity relative to controls, however, following challenge with scopolamine (1 mg/kg, IP) at 2, 4, 6, 8, and 12 weeks after treatment. These data indicate that acute exposure to CPF in adult rats can cause long-term neurobehavioral changes that may persist following the recovery of neurochemical parameters associated with exposure and tolerance to cholinesterase inhibitors.

Isolation of lymphocyte surface antigens. II. Identification of non-beta 2 -microglobulin-associated human T cell-specific antigen.

Iodinated cell surface components from human thymus lymphocytes labeled by the lactoperoxidase method, were solubilized by papain digestion and then 3 M KCl extraction of the residual cell pellet. Antiserum to human thymus bound three components from this material, mol. wt. approximately equal to 40 000, 20 000 and 12 000 daltons. This antiserum was absorbed with cultured human lymphoblasts (CHL) until it no longer bound CHL antigens or the HLA-beta 2-microglobulin complex. It continued to bind labeled antigens from thymus, peripheral blood lymphocytes and "T" cell-enriched fraction of tonsil lymphocytes. The absorbed antiserum bound a component from papain-solubilized thymus antigens which had an estimated molecular weight of approximately 40 000 daltons and which was not associated with beta 2-microglobulin. This component seemed to be a human T cell-specific antigen.

The redox state in lymphocytes from patients with rheumatoid arthritis.

Our study was designed to quantitate levels of NAD+, NADH, NADP(H), and ATP in peripheral blood lymphocytes with and without mitogenic stimulation from patients with rheumatoid arthritis (RA). No differences were found in patients with RA and healthy controls. Our data suggest the ability of the redox system of circulating peripheral lymphocytes to respond to mitogenic stimulation in patients with RA is not markedly impaired.

Increased carbonyl content of proteins in synovial fluid from patients with rheumatoid arthritis.

The carbonyl content of proteins in the synovial fluid (SF) of patients with rheumatoid arthritis was significantly (p less than or equal to 0.10) elevated over levels in the SF of patients with osteoarthritis (OA). Other indicators of oxidative damage including catalse, ceruloplasmin, ferritin and superoxide dismutase also showed statistically significant differences (p less than or equal to 0.05) compared to patients with OA.

Activation-dependent subconductance levels in the drk1 K channel suggest a subunit basis for ion permeation and gating.

Ion permeation and channel opening are two fundamental properties of ion channels, the molecular bases of which are poorly understood. Channels can exist in two permeability states, open and closed. The relative amount of time a channel spends in the open conformation depends on the state of activation. In voltage-gated ion channels, activation involves movement of a charged voltage sensor, which is required for channel opening. Single-channel recordings of drk1 K channels expressed in Xenopus oocytes suggested that intermediate current levels (sublevels) may be associated with transitions between the closed and open states. Because K channels are formed by four identical subunits, each contributing to the lining of the pore, it was hypothesized that these sublevels resulted from heteromeric pore conformations. A formal model based on this hypothesis predicted that sublevels should be more frequently observed in partially activated channels, in which some but not all subunits have undergone voltage-dependent conformational changes required for channel opening. Experiments using the drk1 K channel, as well as drk1 channels with mutations in the pore and in the voltage sensor, showed that the probability of visiting a sublevel correlated with voltage- and time-dependent changes in activation. A subunit basis is proposed for channel opening and permeation in which these processes are coupled.

GYGD pore motifs in neighbouring potassium channel subunits interact to determine ion selectivity.

Cells maintain a negative resting membrane potential through the constitutive activity of background K+ channels. A novel multigene family of such K+ channels has recently been identified. A unique characteristic of these K+ channels is the presence of two homologous, subunit-like domains, each containing a pore-forming region. Sequence co-variations in the GYGD signature motifs of the two pore regions suggested an interaction between neighbouring pore domains. Mutations of the GYGD motif in the rat drk1 (Kv2.1) K+ channel showed that the tyrosine (Y) position was important for K+ selectivity and single channel conductance, whereas the aspartate (D) position was a critical determinant of open state stability. Tandem constructs engineered to mimic the GYGx-GxGD pattern seen in two-domain K+ channels delineated a co-operative intersubunit interaction between the Y and D positions, which determined ion selectivity, conductance and gating. In the bacterial KcsA K+ channel crystal structure, the equivalent aspartate residue (D80) does not directly interact with permeating K+ ions. However, the data presented here show that the D position is able to fine-tune ion selectivity through a functional interaction with the Y position in the neighbouring subunit. These data indicate a physiological basis for the extensive sequence variation seen in the GYGD motifs of two-domain K+ channels. It is suggested that a cell can precisely regulate its resting membrane potential by selectively expressing a complement of two-domain K+ channels.

Acid absorption in the canine duodenum.

Alterations in composition of isosmotic acid solutions were studied in exteriorized segments of the proximal (Brunner's gland area) and distal canine duodenum, mounted in lucite chambers. Varying concentrations of HCl (40, 80, 120, 160 mEq/l) made isotonic by the addition of NaCl were instilled into the chamber, removed in 15 minutes and analyzed for volume, electrolytes, protein content and osmolality. Both proximal and distal duodenal mucosa modified the instilled solution with a loss of H+ and a gain in Na+ and K+, which occurred at similar rates independent of the acid concentration of the instilled solution. The rate of ionic movement was twice that for the antrum, and 30-100 times that of the fundus. Calculated H+ loss across the entire duodenal mucosa at these rates could account for 17.5% of the peak acid output from the canine stomach. The loss of H+ could not be accounted for on the basis of neutralization and probably represented transmucosal insorption. In addition to the neutralization of gastric acid by pancreatic juice and bile, duodenal mucosa thus plays an important role in the maintenance of intraluminal pH. Duodenal mucosal permeability to H+ may be related to the vulnerability of the duodenal mucosa to acid-peptic ulceration.