Surgical Treatment of Severe Attacks of Ulcerative Colitis,with Special Reference to the Advantages of Early Operation

The management and outcome of 258 severe attacks of ulcerative colitis from 1952 to 1969 has been reviewed. If remission did not occur during an initial course of intensive medical treatment, including administration of corticosteroids, operation (generally ileostomy with proctocolectomy or subtotal colectomy) was performed. This took place some 12 to 17 days after admission as a rule during the years 1952-63, but usually within five to seven days from 1964 to 1969.Roughly half the attacks underwent spontaneous remission during the two periods, but the medical mortality was 4·8% in the former and 0·7% in the latter, the operative mortality 20·0 and 7·0%, and the overall mortality 11·3 and 4.5% respectively. The lowering of the mortality was particularly striking in severe first attacks and in severe attacks in patients over 60 years of age.Perforation of the colon was found in 21 cases, or nearly 20% of 112 patients coming to operation during attacks, being commoner in the first period (32·5%) than in the second (11·1%). The immediate mortality of all such operations was 11·6%; in cases with perforation it was 28·6%.Acute colonic dilatation was observed in 28 cases. All but one were treated by emergency colectomy, at which the colon was noted to be perforated in 11. The mortality of these operations was 18·5%.Follow-up of the 140 patients who survived without coming to operation during their attacks shows that 52 (37·1%) subsequently underwent surgical treatment either during further attacks or electively.Though all 258 attacks were thought at the time to be due to ordinary ulcerative colitis, subsequent pathological examination of operative specimens derived from 98 patients who came to urgent or subsequent operation during the 1964-9 period revealed that the lesion in the large bowel was Crohn''s disease in 17 instances.     

Combined Treatment of Xenon and Hypothermia in Newborn Rats - Additive or Synergistic Effect?

BackgroundBreathing the inert gas Xenon (Xe) enhances hypothermic (HT) neuroprotection after hypoxia-ischemia (HI) in small and large newborn animal models. The underlying mechanism of the enhancement is not yet fully understood, but the combined effect of Xe and HT could either be synergistic (larger than the two effects added) or simply additive. A previously published study, using unilateral carotid ligation followed by hypoxia in seven day old (P7) rats, showed that the combination of mild HT (35°C) and low Xe concentration (20%), both not being neuroprotective alone, had a synergistic effect and was neuroprotective when both were started with a 4 h delay after a moderate HI insult. To examine whether another laboratory could confirm this finding, we repeated key aspects of the study.Design/MethodsAfter the HI-insult 120 pups were exposed to different post-insult treatments: three temperatures (normothermia (NT) NT_37°C, HT_35°C, HT_32°C) or Xe concentrations (0%, 20% or 50%) starting either immediately or with a 4 h delay. To assess the synergistic potency of Xe-HT, a second set (n = 101) of P7 pups were exposed to either HT_35°C+Xe_0%, NT+Xe_20% or a combination of HT_35°C+Xe_20% starting with a 4 h delay after the insult. Brain damage was analyzed using relative hemispheric (ligated side/unligated side) brain tissue area loss after seven day survival.ResultsImmediate HT_32°C (p = 0.042), but not HT_35°C significantly reduced brain injury compared to NT_37°C. As previously shown, adding immediate Xe_50% to HT_32°C increased protection. Neither 4 h-delayed Xe_20%, nor Xe_50% at 37°C significantly reduced brain injury (p>0.050). In addition, neither 4 h-delayed HT_35°C alone, nor HT_35°C+Xe_20% reduced brain injury. We found no synergistic effect of the combined treatments in this experimental model.ConclusionsCombining two treatments that individually were ineffective (delayed HT_35°C and delayed Xe_20%) did not exert neuroprotection when combined, and therefore did not show a synergistic treatment effect.     

Quantification of NADH:ubiquinone oxidoreductase (complex I) content in biological samples

Impairments in mitochondrial energy metabolism have been implicated in human genetic diseases associated with mitochondrial and nuclear DNA mutations, neurodegenerative and cardiovascular disorders, diabetes, and aging. Alteration in mitochondrial complex I structure and activity has been shown to play a key role in Parkinson''s disease and ischemia/reperfusion tissue injury, but significant difficulty remains in assessing the content of this enzyme complex in a given sample. The present study introduces a new method utilizing native polyacrylamide gel electrophoresis in combination with flavin fluorescence scanning to measure the absolute content of complex I, as well as α-ketoglutarate dehydrogenase complex, in any preparation. We show that complex I content is 19 ± 1 pmol/mg of protein in the brain mitochondria, whereas varies up to 10-fold in different mouse tissues. Together with the measurements of NADH-dependent specific activity, our method also allows accurate determination of complex I catalytic turnover, which was calculated as 10⁴ min⁻¹ for NADH:ubiquinone reductase in mouse brain mitochondrial preparations. α-ketoglutarate dehydrogenase complex content was determined to be 65 ± 5 and 123 ± 9 pmol/mg protein for mouse brain and bovine heart mitochondria, respectively. Our approach can also be extended to cultured cells, and we demonstrated that about 90 × 10³ complex I molecules are present in a single human embryonic kidney 293 cell. The ability to determine complex I content should provide a valuable tool to investigate the enzyme status in samples after in vivo treatment in mutant organisms, cells in culture, or human biopsies.     

TEMPERATURE CHARACTERISTICS FOR PULSATION FREQUENCY IN GONIONEMUS

The frequency of contraction of the bell of Gonionemus was studied in relation to temperature, with intact animals and also where different operations were made on the nervous system. A number of values of µ are found for intact animals namely 8,100±, 10,500±, 32,000± and 22,500±, with critical temperatures at 9.6°, 12.3°, and 14.0°. Four different classes of operations were used: (1) Animals where the nerve ring was cut on two opposite sides of the bell; the µ values found are 10,500± and 21,300±, with a critical temperature at 13.4°. (2) Animals with four cuts through the nerve ring gave µ = 10,600 ± and µ = 21,000, with a critical temperature at 13.1°. (3) In animals where the bell was cut in half the temperature characteristic was found to be 16,900. And finally (4) in the animals where the nerve ring was totally removed µ values of 8,100, 16,000±, and 29,000 were found, with critical temperatures at 15.0° and 9.4°. These results are discussed from the standpoint of the theory which supposes that definite "temperature characteristics" may be associated with the functional activity of particular elements in a complex functional unit, and that these elements may be separately studied and identified by suitable experimental procedures involving the magnitudes of the respective temperature characteristics and the locations of associated critical temperatures. The swimming bell of medusæ with its marginal sense organs permits a fairly direct approach to such questions. It is found that even slight injuries to the marginal nerve ring, for example, produce specific modifications in the temperature relations which are different from those appearing when the organism is cut in half.     

TEMPERATURE CHARACTERISTICS FOR FREQUENCY OF RESPIRATORY MOVEMENTS IN YOUNG MAMMALS

The internal temperature of 2 day old mice deviates by +0.01° to +3.0°C. from the environmental temperature over a range of 24°. The undeveloped temperature control allows rhythmic activities in this mammalian material to be readily subjected to the analysis afforded by temperature characteristics, and thus makes possible some insight into the physicochemical events controlling vital processes in entire uninjured mammals. The thermal increments and critical temperatures obtained point to a similarity in the controlling system of reactions for both homothermic and poikilothermic organisms. For frequency of respiratory movements the increments 12,340 (19.6° to 35.2°C.); 28,340 or 36,500 (15.5° to 19.6°C.) are most frequently found (thirteen cases). Rarely µ = 8,450, 33,000, or 18,340 (two cases). The last increment is either associated with µ = 36,000 below 20°, or extends unbroken throughout the whole range (one case).     

Effect of temperature conditioning on chilling injury of cucumber cotyledons: possible role of abscisic Acid and heat shock proteins

Endogenous abscisic acid levels and induced heat shock proteins were measured in tissue exposed for 6 hours to temperatures that reduced their subsequent chilling sensitivity. One-centimeter discs excised from fully expanded cotyledons of 11-day-old seedlings of cucumber (Cucumis sativus L., cv Poinsett 76) were exposed to 12.5 or 37°C for 6 hours followed by 4 days at 2.5 or 12.5°C. Ion leakage, a qualitative indicator of chilling injury, increased after 2 to 3 day exposure to 2.5°C, but not to 12.5°C, a nonchilling temperature. Exposure to 37°C before chilling significantly reduced the rate of ion leakage by about 60% compared to tissue exposed to 12.5°C before chilling, but slightly increased leakage compared to tissue exposed to 12.5 or 37°C and held at the nonchilling temperature of 12.5°C. There was no relationship between abscisic acid content following exposure to 12.5 or 37°C and chilling tolerance. Five heat shock proteins, with apparent molecular mass of 25, 38, 50, 70, and 80 kilodaltons, were induced by exposure to 37 or 42°C for 6 hours, and their appearance coincided with increased chilling resistance. Heat shock treatments reduced the synthesis of three proteins with apparent molecular mass of 14, 17, and 43 kilodaltons. Induction of heat shock proteins could be a possible cause of reduced chilling injury in tissue exposed to 37 or 42°C.     

Global Brain Blood-Oxygen Level Responses to Autonomic Challenges in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is accompanied by brain injury, perhaps resulting from apnea-related hypoxia or periods of impaired cerebral perfusion. Perfusion changes can be determined indirectly by evaluation of cerebral blood volume and oxygenation alterations, which can be measured rapidly and non-invasively with the global blood oxygen level dependent (BOLD) signal, a magnetic resonance imaging procedure. We assessed acute BOLD responses in OSA subjects to pressor challenges that elicit cerebral blood flow changes, using a two-group comparative design with healthy subjects as a reference. We separately assessed female and male patterns, since OSA characteristics and brain injury differ between sexes. We studied 94 subjects, 37 with newly-diagnosed, untreated OSA (6 female (age mean ± std: 52.1±8.1 yrs; apnea/hypopnea index [AHI]: 27.7±15.6 events/hr and 31 male 54.3±8.4 yrs; AHI: 37.4±19.6 events/hr), and 20 female (age 50.5±8.1 yrs) and 37 male (age 45.6±9.2 yrs) healthy control subjects. We measured brain BOLD responses every 2 s while subjects underwent cold pressor, hand grip, and Valsalva maneuver challenges. The global BOLD signal rapidly changed after the first 2 s of each challenge, and differed in magnitude between groups to two challenges (cold pressor, hand grip), but not to the Valsalva maneuver (repeated measures ANOVA, p<0.05). OSA females showed greater differences from males in response magnitude and pattern, relative to healthy counterparts. Cold pressor BOLD signal increases (mean ± adjusted standard error) at the 8 s peak were: OSA 0.14±0.08% vs. Control 0.31±0.06%, and hand grip at 6 s were: OSA 0.08±0.03% vs. Control at 0.30±0.02%. These findings, indicative of reduced cerebral blood flow changes to autonomic challenges in OSA, complement earlier reports of altered resting blood flow and reduced cerebral artery responsiveness. Females are more affected than males, an outcome which may contribute to the sex-specific brain injury in the syndrome.     

Operative Treatment of Terrible Triad of the Elbow via Posterolateral and Anteromedial Approaches

The aim of the study was to explore the clinical outcome of posterolateral and anteromedial approaches in treatment of terrible triad of the elbow. The study involved 12 patients with closed terrible triad of the elbow treated by posterolateral and anteromedial approaches between January 2010 and June 2012. The mechanism of injury included fall from height in 9 patients and traffic accident in 3. According to O’Driscoll classification for fractures of the ulnar coronoid, there were 11 patients with type Ⅰ and 1 with type Ⅱ fractures. According to Mason classification for fractures of the radial head, there were 3 patients with type Ⅰ, 7 with type Ⅱ and 2 with type Ⅲ fractures. All patients were followed up for 12-27 months (average 15.5 months), which showed no pain or severe pain in all patients except for 2 patients with mild pain. At the last follow-up, the mean flexion was for 125°(range, 90°-140°), the mean extension loss for 20°(range, 0°-70°), the mean pronation for 66°(range, 20°-85°) and the mean supination for 60°(range, 30°-85°). The bony union time was 8-14 weeks (average 11 weeks) and the elbows were stable in flexion-extension and varus-valgus in all patients. The elbows maintained a concentric reduction of both the ulnotrochlear and the radiocapitellar articulation. Mild heterotopic ossification of the elbow occurred in 3 patients at 6 months after operation and mild degenerative change in 1 patient at 18 months after operation. The Broberg and Morrey elbow performance score was 82 points (range, 58-98 points). The results were excellent in 6 patients, good in 4, fair in 1 and poor in 1, with excellence rate of 83.3%. The results showed that the combined posterolateral and anteromedial approaches can facilitate the reduction and fixation of terrible triad of the elbow. Repair of radial head, coronoid, medial and lateral collateral ligaments can sufficiently restore the elbow stability, allow early postoperative motion and enhance the functional recovery.     

THE RELATION BETWEEN TEMPERATURE AND THE PEDAL RHYTHM OF BALANUS

1. The relation of temperature to the pedal rhythm of Balanus balanoides L. has been studied under otherwise constant conditions. 2. The frequency of movement increases with temperature, showing three groups of thermal increments and three critical temperatures. Five animals yielded µ = 5,700 above 14.5° C. and 12,100 below; 3 gave µ = 7,800 above 9.3° and 22,500 below; while 9 showed µ = 9,500 above 8.1° and 22,100 below. 3. The upper critical temperatures, above which different effects appeared in different animals were 23.4°, 26.0°, and 27.0°. Above 27.0° none of the valves remained open. 4. Excepting the values 5,700 and 9,500, the increments are similar to those previously found to be associated with respiratory and with neuromuscular activities. 5. Dilution of the sea water with from 3 to 4 per cent fresh water decreases the rate without altering the increments. More than 4 per cent dilution causes irregularity.     

Gradual Rewarming with Gradual Increase in Pressure during Machine Perfusion after Cold Static Preservation Reduces Kidney Ischemia Reperfusion Injury

In this study we evaluated whether gradual rewarming after the period of cold ischemia would improve organ quality in an Isolated Perfused Kidney Model. Left rat kidneys were statically cold stored in University of Wisconsin solution for 24 hours at 4°C. After cold storage kidneys were rewarmed in one of three ways: perfusion at body temperature (38°C), or rewarmed gradually from 10°C to 38°C with stabilization at 10°C for 30 min and rewarmed gradually from 10°C to 38°C with stabilization at 25°C for 30 min. In the gradual rewarming groups the pressure was increased stepwise to 40 mmHg at 10°C and 70 mmHg at 25°C to counteract for vasodilatation leading to low perfusate flows. Renal function parameters and injury biomarkers were measured in perfusate and urine samples. Increases in injury biomarkers such as aspartate transaminase and lactate dehydrogenase in the perfusate were lower in the gradual rewarming groups versus the control group. Sodium re-absorption was improved in the gradual rewarming groups and reached significance in the 25°C group after ninety minutes of perfusion. HSP-70, ICAM-1, VCAM-1 mRNA expressions were decreased in the 10°C and 25°C groups. Based on the data kidneys that underwent gradual rewarming suffered less renal parenchymal, tubular injury and showed better endothelial preservation. Renal function improved in the gradual rewarming groups versus the control group.     

TEMPERATURE CHARACTERISTICS FOR THE OXYGEN CONSUMPTION OF GERMINATING SEEDS OF LUPINUS ALBUS AND ZEA MAYS

The rate of oxygen consumption by germinating seeds of Lupinus albus and of Zea mays was studied as a function of temperature (7–26°C.). The Warburg manometer technique was used, with slight modifications. Above and below a critical temperature at 19.5°C. the temperature characteristic for oxygen consumption by Lupinus albus was found to be µ = 11,700± and 16,600 respectively. The same critical temperature was encountered in the case of Zea mays, with temperature characteristics µ = 13,100± above and µ = 21,050 below that temperature.     

Diapause Induction and Termination in the Small Brown Planthopper,Laodelphax striatellus (Hemiptera: Delphacidae)

The small brown planthopper, Laodelphax striatellus (Fallén) enters the photoperiodic induction of diapause as 3rd or 4th instar nymphs. The photoperiodic response curves in this planthopper showed a typical long-day response type with a critical daylength of approximately 11 h at 25°C, 12 h at 22 and 20°C and 12.5 h at 18°C, and diapause induction was almost abrogated at 28°C. The third stage was the most sensitive stage to photoperiod. The photoperiodic response curve at 20°C showed a gradual decline in diapause incidence in ultra-long nights, and continuous darkness resulted in 100% development. The required number of days for a 50% response was distinctly different between the short- and long-night cycles, showing that the effect of one short night was equivalent to the effect of three long nights at 18°C. The rearing day length of 12 h evoked a weaker intensity of diapause than did 10 and 11 h. The duration of diapause was significantly longer under the short daylength of 11 h than it was under the long daylength of 15 h. The optimal temperature for diapause termination was 26 and 28°C. Chilling at 5°C for different times did not shorten the duration of diapause but significantly lengthened it when chilling period was included. In autumn, 50% of the nymphs that hatched from late September to mid-October entered diapause in response to temperatures below 20°C. The critical daylength in the field was between 12 h 10 min and 12 h 32 min (including twilight), which was nearly identical to the critical daylength of 12.5 h at 18°C. In spring, overwintering nymphs began to emerge in early March-late March when the mean daily temperature rose to 10°C or higher.     

Response of Asthmatics to Isoprenaline and Salbutamol Aerosols Administered by Intermittent Positive-pressure Ventilation

The bronchodilator and cardiac effects produced by aerosols of 0·5% isoprenaline and of 0·25, 0·5, and 1% salbutamol administered in 40% oxygen by intermittent positive-pressure ventilation were compared in 24 asthmatic patients. Isoprenaline and salbutamol in concentrations of 0·5% were equipotent in peak bronchodilator effect; salbutamol was superior in total bronchodilator effect and duration of average effect, but the peak bronchodilator effect occurred earlier after isoprenaline. Significantly greater tachycardia was produced by 0·5% isoprenaline than by the same concentration of salbutamol. The 0·25, 0·5, and 1% concentrations of salbutamol had about the same peak bronchodilator effect, but there was a stepwise increase in total effect and duration of average effect in relation to the concentration used. A similar stepwise increase in heart rate was also noted, but with all concentrations this was significantly less than with 0·5% isoprenaline. It was concluded that a 0·5% solution of salbutamol, which provided maximal bronchodilatation without important tachycardia, was therapeutically superior to the other three treatments.     

Chilling-Induced Ethylene Production in Cucumbers (Cucumis sativus L.)

1-Aminocyclopropane-1-carboxylic acid (ACC) level, ACC synthase activity, and ethylene production in cucumbers (Cucumis sativus L.) remain low while the fruit are held at a temperature which causes chilling injury (2.5°C) and increase rapidly only upon transfer to warmer temperatures. The increase in ACC synthase activity during the warming period is inhibited by cycloheximide but not cordycepin or α-amanitin. Our data indicate that the synthesis of ACC synthase, which results in increased ACC levels and accelerated ethylene production, occurs only upon warming, possibly from a message produced or unmasked during the chilling period. Ethylene production by chilled (2.5°C) cucumbers increased very little upon transfer to 25°C if the fruit were chilled for more than 4 days. The fruit held for 4 days or longer showed a large increase in ACC levels but little ethylene production even in the presence of exogenous ACC. This suggests that the system which converts ACC to ethylene is damaged by prolonged exposure to the chilling temperature. Cucumbers stored at a low but nonchilling temperature (13°C) showed very little change in ACC level, ethylene production, or ACC synthase activity even after transfer to 25°C.     

Studies of Frost Hardiness in Woody Plants. II. Effect of Temperature on Hardening

The effect of temperature on hardening was studied at temperatures ranging from 0° to −20° using twigs of willow and poplar. In October and in late April when the twigs are not very frost hardy, hardening at 0° produced a considerable increase in their frost hardiness, although the effectiveness of hardening at 0° decreased with a decrease in the environmental temperature. In twigs which could withstand continuous freezing without injury, hardening at −3° to −5° was most effective in increasing the frost hardiness of the twigs. Below −20°, only negligible increase was observed either in frost hardiness or sugar content.

The rate of starch to sugar conversion differed remarkably in different twig tissues. The starch in xylem was more slowly converted to sugar than that in the cortex. The optimum temperature for converting starch into sugar during frost hardening was also found to be −3° to −5°. In addition, the greater the effectiveness of the hardening treatment, the greater the rate of conversion from starch to sugar. The frost hardiness of a twig is closely related to the sugar content of the twig, especially in the xylem.

     

ON THE TEMPERATURE CHARACTERISTICS FOR FREQUENCY OF BREATHING MOVEMENTS IN INBRED STRAINS OF MICE AND IN THEIR HYBRID OFFSPRING. I

Young mice of a selected line of the dilute brown strain of mice exhibit over the range 15–25°C. (body temperature) a relation of frequency of breathing movements to temperature such that when fitted by the Arrhenius equation the data give a value for the constant µ of 24,000± calories or, less frequently, 28,000±. Young mice of an inbred albino strain show over the range 15–20°C. a value of µ = 34,000±, or, less frequently, 14,000±, with a critical temperature at about 20°C. and a value of µ = 14,000± above 20°C. The F₁ hybrids of these two strains, and the backcross generations to either parent strain, exhibit only those four values of the temperature characteristic observed in the parent strains and none other. One may therefore speak of the inheritance of the value of the constant µ, but the inheritance shows in this instance no Mendelian behavior. Furthermore there appears to be inherited the occurrence (or absence) of a critical temperature at 20°C. These experiments indicate the "biological reality" of the temperature characteristics.     

The Shift of Thermoneutral Zone in Striped Hamster Acclimated to Different Temperatures

Temperature affects all biological functions and will therefore modulate ecologically significant interactions between animals and their environment. Here, we examined the effect of ambient temperature (T_a) on the thermal biology and energy budget in striped hamsters acclimated to cold (5°C), warm (21°C) and hot temperatures (31°C). Thermoneutral zone (TNZ) was 22.5–32.5°C, 25–32.5°C and 30–32.5°C in the cold-, warm- and hot-acclimated hamsters, respectively. The cold acclimation decreased the lower critical temperature and made the TNZ wider, and hot exposure elevated the lower critical temperature, resulting in a narrow TNZ. Within the TNZ, cold-acclimated hamsters showed a significantly higher rate of metabolism and thermogenesis than those acclimated to hot temperature. Digestive enzymes activities, including intestinal sucrase, maltase, L-alanine aminopeptidase-N and leucine aminopeptidase were higher in the cold than in the hot. The changes in metabolic rate and thermogenesis at different temperatures were in parallel with cytochrome c oxidase activity and uncoupling protein 1 gene expression of brown adipose tissue. This suggests that the shift of the lower critical temperature of TNZ is possibly associated with the rate of metabolism and thermogenesis, as well as with the digestive capacity of the gastrointestinal tract at different T_a. The upper critical temperature of TNZ may be independent of the changes in T_a. The changes of lower critical temperature of TNZ are an important strategy in adaption to variations of T_a.     

Bacterial ice nucleation: a factor in frost injury to plants

Heterogeneous ice nuclei are necessary, and the common epiphytic ice nucleation active (INA) bacteria Pseudomonas syringae van Hall and Erwinia herbicola (Löhnis) Dye are sufficient to incite frost injury to sensitive plants at −5°C. The ice nucleation activity of the bacteria occurs at the same temperatures at which frost injury to sensitive plants occurs in nature. Bacterial ice nucleation on leaves can be detected at about −2°C, whereas the leaves themselves, i.e. without INA bacteria, contain nuclei active only at much lower temperatures. The temperature at which injury to plants occurs is predictable on the basis of the ice nucleation activity of leaf discs, which in turn depends on the number and ice nucleation activity of their resident bacteria. Bacterial isolates which are able to incite injury to corn at −5°C are always active as ice nuclei at −5°C. INA bacteria incited frost injury to all of the species of sensitive plants tested.     

Impacts of growth form and phylogenetic relatedness on seed germination: A large‐scale analysis of a subtropical regional flora

Plant regeneration strategy plays a critical role in species survival and can be used as a proxy for the evolutionary response of species to climate change. However, information on the effects of key plant traits and phylogenetic relatedness on seed germination is limited at large regional scales that vary in climate. To test the hypotheses that phylogenetic niche conservatism plays a critical force in shaping seed ecophysiological traits across species, and also drives their response to climatic fluctuation, we conducted a controlled experiment on seed germination and determined the percentage and rate of germination for 249 species in subtropical China under two temperature regimes (i.e., daily 25°C; daily alternating 25/15°C for each 12 hr). Germination was low with a skewed distribution (mean = 38.9% at 25°C, and 43.3% at 25/15°C). One fifth of the species had low (<10%) and slow (4–30 days) germination, and only a few (8%) species had a high (>80%) and rapid (1.2–6.6 days) germination. All studied plant traits (including germination responses) showed a significant phylogenetic signal, with an exception of seed germination percentage under the alternating temperature scenario. Generalized linear models (GLMs) and phylogenetic generalized estimation equations (GEEs) demonstrated that growth form and seed dispersal mode were strong drivers of germination. Our experimental study highlights that integrating plant key traits and phylogeny is critical to predicting seed germination response to future climate change.     

Deletion of SA β‐Gal+ cells using senolytics improves muscle regeneration in old mice

Systemic deletion of senescent cells leads to robust improvements in cognitive, cardiovascular, and whole‐body metabolism, but their role in tissue reparative processes is incompletely understood. We hypothesized that senolytic drugs would enhance regeneration in aged skeletal muscle. Young (3 months) and old (20 months) male C57Bl/6J mice were administered the senolytics dasatinib (5 mg/kg) and quercetin (50 mg/kg) or vehicle bi‐weekly for 4 months. Tibialis anterior (TA) was then injected with 1.2% BaCl₂ or PBS 7‐ or 28 days prior to euthanization. Senescence‐associated β‐Galactosidase positive (SA β‐Gal+) cell abundance was low in muscle from both young and old mice and increased similarly 7 days following injury in both age groups, with no effect of D+Q. Most SA β‐Gal+ cells were also CD11b+ in young and old mice 7‐ and 14 days following injury, suggesting they are infiltrating immune cells. By 14 days, SA β‐Gal+/CD11b+ cells from old mice expressed senescence genes, whereas those from young mice expressed higher levels of genes characteristic of anti‐inflammatory macrophages. SA β‐Gal+ cells remained elevated in old compared to young mice 28 days following injury, which were reduced by D+Q only in the old mice. In D+Q‐treated old mice, muscle regenerated following injury to a greater extent compared to vehicle‐treated old mice, having larger fiber cross‐sectional area after 28 days. Conversely, D+Q blunted regeneration in young mice. In vitro experiments suggested D+Q directly improve myogenic progenitor cell proliferation. Enhanced physical function and improved muscle regeneration demonstrate that senolytics have beneficial effects only in old mice.