Progressive resistance-loaded voluntary wheel running increases hypertrophy and differentially affects muscle protein synthesis, ribosome biogenesis, and proteolytic markers in rat muscle.

We examined if 6 weeks of progressive resistance-loaded voluntary wheel running in rats induced plantaris, soleus, and/or gastrocnemius hypertrophy and/or affected markers of translational efficiency, ribosome biogenesis, and markers of proteolysis. For 6 weeks, 8 male Sprague-Dawley rats (~9-10 weeks of age, ~300-325 g) rats were assigned to the progressive resistance-loaded voluntary wheel running model (EX), and ten rats were not trained (SED). For EX rats, the wheel-loading paradigm was as follows - days 1-7: free-wheel resistance, days 8-15: wheel resistance set to 20%-25% body mass, days 16-24: 40% body mass, days 25-32: 60% body mass, days 33-42: 40% body mass. Following the intervention, muscles were analysed for markers of translational efficiency, ribosome biogenesis, and muscle proteolysis. Raw gastrocnemius mass (+13%, p < .01), relative (body mass-corrected) gastrocnemius mass (+16%, p < .001), raw plantaris mass (+13%, p < .05), and relative plantaris mass (+15%, p < .01) were greater in EX vs. SED rats. In spite of gastrocnemius hypertrophy, EX animals presented a 54% decrease in basal muscle protein synthesis levels (p < .01), a 125% increase in pan 4EBP1 levels (p < .001) and a 31% decrease in pan eIF4E levels (p < .05). However, in relation to SED animals, EX animals presented a 70% increase in gastrocnemius c-Myc protein levels (p < .05). Most markers of translational efficiency and ribosome biogenesis were not altered in the plantaris or soleus muscles of EX vs. SED animals. Gastrocnemius F-box protein 32 and poly-ubiquinated protein levels were approximately 150% and 200% greater in SED vs. EX rats (p < .001). These data suggest that the employed resistance training model increases hind limb muscle hypertrophy, and this may be mainly facilitated through reductions in skeletal muscle proteolysis, rather than alterations in ribosome biogenesis or translational efficiency.

Effects of testosterone treatment on markers of skeletal muscle ribosome biogenesis.

The effects of testosterone (TEST) treatment on markers of skeletal muscle ribosome biogenesis in vitro and in vivo were examined. C2 C12 myotubes were treated with 100 nm TEST for short-term (24-h) and longer-term (96-h) treatments. Moreover, male 10-month-old Fischer 344 rats were housed for 4 weeks, and the following groups were included in this study: (i) Sham-operated (Sham) rats, (ii) orchiectomised rats (ORX) and (iii) ORX+TEST-treated rats (7.0 mg week-1 ). For in vitro data, TEST treatment increased c-Myc mRNA expression by 38% (P = 0.004) after 96 h, but did not affect total RNA, 47S pre-rRNA, Raptor mRNA, Nop56 mRNA, Bop1 mRNA, Ncl mRNA at 24 h or 96 h following the treatment. For in vivo data, ORX decreased levator ani/bulbocavernosus (LABC) myofibril protein versus Sham (P = 0.006), whereas ORX+TEST (P = 0.015) rescued this atrophic effect. ORX also decreased muscle ribosome content (total RNA) compared to Sham (P = 0.046), whereas ORX+TEST tended to rescue this effect (P = 0.057). However, other markers of ribosome biogenesis including c-Myc mRNA, Nop56 mRNA, Bop1 mRNA, Ncl mRNA decreased with ORX independently of TEST treatments (P < 0.05). Finally, lower phospho-(Ser235/236)-to-total rps6 protein and lower rpl5 protein levels existed in ORX+TEST rats versus other treatments, suggesting that chronic TEST treatment may lower translational capacity.

Multi-strain probiotic improves subjective sleep quality with no impact on body composition, hemodynamics, and physical activity.

The objective of the study was to examine the impact of a multi-strain probiotic (MSP) on sleep, physical activity, and body composition changes. We used a randomised, double-blind, placebo-controlled approach with 70 healthy men and women (31.0 ± 9.5 years, 173.0 ± 10.4 cm, 73.9 ± 13.8 kg, 24.6 ± 3.5 kg/m2) supplemented daily with MSP (4 × 109 live cells Limosilactobacillus fermentum LF16, Lacticaseibacillus rhamnosus LR06, Lactiplantibacillus plantarum LP01, and Bifidobacterium longum 04; Probiotical S.p.A., Novara, Italy) or placebo (PLA). In response to supplementation (after 0, 2, 4, and 6 weeks of supplementation) and 3 weeks after stopping supplementation, participants had subjective (Pittsburgh Sleep Quality Index, PSQI) and objective sleep indicators, body composition, daily physical activity and resting hemodynamics assessed. Subjective sleep quality indicators using the PSQI (sleep latency, sleep disturbance, and global PSQI score) improved ( P < 0.05) at various time points with MSP supplementation. Systolic blood pressure in PLA increased ( P < 0.05) after 6 weeks of supplementation with no change in MSP. No changes ( P > 0.05) in sleep (hours asleep, minutes awake, number of times awake) or physical activity (step count, minutes of sedentary activity, total active minutes) metrics assessed by the wearable device were observed. Additionally, no changes in resting heart rate, diastolic blood pressure, and body composition were discerned. In conclusion, MSP supplementation improved the subjective ability to fall asleep faster and disturbances experienced during sleep, which resulted in improved overall sleep quality as assessed by the PSQI. No differences in other sleep indicators, physical activity, hemodynamics, and body composition were observed during or following MSP supplementation. Registered at clinicaltrials.gov: NCT05343533.

Effects of oxybarbiturates on the germination behaviour of Impatiens bolstii pollen.

Swelling of and cytoplasmic streaming within the grain, germination pore expansion, and pollen tube emergence, in that order, constitute the normal germination pattern of Impatiens holstii pollen grains. This normal sequence of events becomes manifest when the pollen grains are placed on water-agar, barbituric acid-agar, and on barbital-agar media whereas this sequence of events is interfered with when the pollen grains are incubated on amytal-agar or on seconal-agar media. Evidence is presented which demonstrates that the normal sequence of events which make up the normal germination pattern of Impatiens holstii pollen grains can be separated from each other by varying the concentrations of the oxybarbiturates amytal and seconal used. Evidence is also presented which indicates that the actions of barbituric acid and the oxybarbiturates barbital, amytal, and seconal on Impatiens holstii pollen germination behaviour correlate well with certain aspects of the pharmacological literature concerning the actions of these organic compounds on the central nervous system (CNS).

Calcium influx from the extracellular space promotes NADH hyperoxidation and electrical dysfunction after anoxia in hippocampal slices.

A characteristic event during reperfusion after cerebral ischemia in vivo, and reoxygenation after anoxia in vitro, is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Current studies have tested the hypothesis that there is a relation among calcium molecules derived from extracellular sources, mitochondrial hyperoxidation, and electrical recovery after anoxia in hippocampal slices. Rat hippocampal slices were superfused with artificial cerebrospinal fluids (ACSF) containing calcium chloride (CaCl2) in concentrations of: 0.5, 1, 2, and 4 mmol/L. Slices were made anoxic and then allowed to recover for 60 minutes. Reduction-oxidation shifts of NADH were measured by rapid-scanning spectrofluorometry. Synaptic activity was indicated by population spike amplitudes in the CA1 pyramidal cell subfield of the hippocampus in response to stimulation of the Schaffer collaterals. Low calcium ACSF concentrations ameliorated NADH hyperoxidation and improved synaptic transmission recovery after anoxia. High calcium ACSF concentrations had opposite effects. These data suggest a link between mitochondrial hyperoxidation and electrical recovery after postanoxia reoxygenation and support the hypothesis that cytosolic calcium overload promotes mitochondrial hyperoxidation and limits electrical recovery.

Soluble IgG aggregates produced by heating remain stable on freeze-drying.

IgG aggregates produced by heating gamma globulin solutions were freeze-dried, kept at 4 degrees C and reconstituted up to 4 months later. By comparison with frozen (-20 degrees C) preparations, only minimal changes in biological reactivity and in physical integrity occurred during this period. These results demonstrate that freeze-dried preparations of heat-aggregated IgG are potentially useful as a reference reagent for the comparative evaluation and standardisation of immune complex assays.

The production of small IgG aggregates by glutaraldehyde cross-linking.

Reaction conditions have been determined for the production of soluble IgG polymers in the size range 10 S to 30 S by covalent cross-linking with glutaraldehyde. This size range is comparable with that of the immune complexes which are frequently found in the circulation of patients with certain autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. The yield of IgG aggregates in this size range is far greater than has been reported for cross-linking by other bifunctional reagents or for aggregation by heating. Glutaraldehyde cross-linked IgG polymers are stable and biologically reactive. They can also be labelled with fluorescein and freeze-dried with minimal loss of integrity or reactivity.

The effect of IgG aggregate size and concentration on reactivity in immune complex assays.

The reactivity of heat-aggregated IgG of known size, in the Raji cell assay, the C1q binding assay and the C1q solid phase radioimmunoassay as a function of concentration, has been investigated. Marked differences were found in the way that the three assays behave when the IgG concentration and aggregate size are varied. These findings indicate the pitfalls in attempting to express the results of immune complex assays performed on biological fluids in terms of equivalent concentrations of aggregated IgG.

Anoxic preconditioning in hippocampal slices: role of adenosine.

Prior studies have shown that sublethal anoxic/ischemic insults may "precondition" and thereby protect tissues such as heart and brain from subsequent insults. In hippocampal slices, we examined two hypotheses: (i) that anoxic preconditioning improves the ability of slices to recover synaptic activity following a second anoxic insult and (ii) that anoxic preconditioning involves adenosine receptors. Hippocampal slices were preconditioned by short periods of anoxia prolonged only until the onset of anoxic depolarization. The slices were then reoxygenated for 30 min, after which a second ("test") anoxic insult was induced. Amplitudes of evoked potentials recovered significantly better after "test" anoxic insults in preconditioned slices. In control slices, transient superfusion with adenosine or an adenosine A1 receptor agonist (2-chloroadenosine) 30 min prior to "test" anoxia markedly improved evoked potential recovery. Administration of 8-cyclopentyl-1,3-dipropylxanthine, an A1 receptor antagonist, blocked the protection afforded by preconditioning. These data support the hypothesis that adenosine, probably by its activation of A1 receptors, is involved in the neuroprotection afforded by anoxic preconditioning in hippocampal slices. Preconditioning insults may have a significant clinical impact, since certain surgical procedures may require, or produce, multiple periods of brain ischemia.

Prolonged anoxic depolarization exacerbates NADH hyperoxidation and promotes poor electrical recovery after anoxia in hippocampal slices.

Mitochondrial dysfunction appears to occur during brain ischemia and following reperfusion. A characteristic event during reoxygenation after anoxia in hippocampal slices is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Earlier studies suggested that calcium influx due to loss of ion homeostasis during anoxia was linked to neuronal damage. Since a link between cytosolic calcium overload and post-anoxic hyperoxidation (PAMHo) has been suggested in previous studies, present studies sought to test the hypothesis that the length of anoxic depolarization can influence hyperoxidation and electrical activity recovery following anoxia in hippocampal slices. Rat hippocampal slices were made anoxic and then allowed to recover for 60 min. The time of anoxia was defined by the time of anoxic depolarization (AD), and slices were divided in five groups: 0.5, 1, 2, 5 and 10 min of AD. Reduction/oxidation shifts of NADH were measured by rapid scanning spectrofluorometry. Synaptic activity was indicated by population spike amplitudes in the CA1 pyramidal cell subfield of the hippocampus in response to stimulation of the Schaffer collaterals. We report here that mitochondrial hyperoxidation and synaptic activity in hippocampal slices are highly sensitive to the time in which slices remain depolarized (AD).

Antioxidants, mitochondrial hyperoxidation and electrical recovery after anoxia in hippocampal slices.

Cerebral injury may occur not only during brain ischemia but also during reperfusion afterward. A characteristic event during reperfusion after cerebral ischemia, or reoxygenation after anoxia in hippocampal slices, is hyperoxidation of the electron carriers of the mitochondrial respiratory chain. Earlier studies suggested that mitochondrial hyperoxidation was produced by an oxyradical mechanism and was linked to neuronal damage. Present studies sought to test this hypothesis by determining whether antioxidants could suppress mitochondrial hyperoxidation and improve electrical recovery after anoxia in hippocampal slices. Both 500 microM ascorbate and 50 microM glutathione decreased post-anoxic hyperoxidation of NADH and improved electrical recovery in hippocampal slices. These data support a role of oxygen free radicals in promoting post-anoxic mitochondrial hyperoxidation and electrical failure, and suggest that these effects of anoxia or ischemia may be linked.