6-hour Delay Research Articles

Delays in Debridement of Open Femoral and Tibial Fractures Increase Risk of Infection.

Infection remains a costly, devastating complication following the treatment of open fractures. The appropriate timing of debridement is controversial, and available evidence has been conflicting. This study is a retrospective analysis of the SIGN (Surgical Implant Generation Network) Surgical Database (SSDB), a prospective registry of fracture cases in predominantly low-resource settings. Skeletally mature patients (≥16 years of age) who returned for follow-up at any time point after intramedullary nailing of an open femoral or tibial fracture were included. Patients were excluded if they had delays in debridement exceeding 7 days after the injury. Utilizing a model adjusting for potential confounders, including patient demographic characteristics, injury characteristics, country income level, and hospital type and resources, local logistic regression analysis was performed to evaluate the probability of infection with increasing time to debridement in 6-hour increments. In this study, 27.3% of patients met the eligibility criteria and returned for follow-up, with a total of 10,651 fractures from 61 countries included. Overall, the probability of infection increased by 0.17% for every 6-hour delay in debridement. On subgroup analysis, the probability of infection increased by 0.23% every 6 hours for Gustilo-Anderson type-III injuries compared with 0.13% for Gustilo-Anderson type-I or II injuries. The infection risk increased every 6 hours by 0.18% for tibial fractures compared with 0.13% for femoral fractures. There was a linear and cumulative increased risk of infection with delays in debridement for open femoral and tibial fractures. Such injuries should be debrided promptly and expeditiously. The size and international nature of this cohort make these findings uniquely generalizable to nearly all environments where such injuries are treated. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Evaluating the effects of radiation and acoustically-stimulated microbubble therapy in an in vivo breast cancer model.

Ultrasound-stimulated microbubbles (USMB) cause localized vascular effects and sensitize tumors to radiation therapy (XRT). We investigated acoustic parameter optimization for combining USMB and XRT. We treated breast cancer xenograft tumors with 500 kHz pulsed ultrasound at varying pressures (570 or 740 kPa), durations (1 to 10 minutes), and microbubble concentrations (0.01 to 1% (v/v)). Radiation therapy (2 Gy) was administered immediately or after a 6-hour delay. Histological staining of tumors 24 hours after treatment detected changes in cell morphology, cell death, and microvascular density. Significant cell death resulted at 570 kPa after a 1-minute exposure with 1% (v/v) microbubbles with or without XRT. However, significant microvascular disruption required higher ultrasound pressure and exposure duration greater than 5 minutes. Introducing a 6-hour delay between treatments (USMB and XRT) showed a similar tumor effect with no further improvement in response as compared to when XRT was delivered immediately after USMB.

Sodium thiosulfate as cisplatin otoprotectant in children: The challenge of when to use it.

Sodium thiosulfate as cisplatin otoprotectant in children: The challenge of when to use it.

The effect of deliberate non-adherence to a norgestrel progestin-only pill: A randomized, crossover study

ObjectivesTo estimate the effects on cervical mucus, ovarian activity and theoretical contraceptive protection of a 6-hour delay and of missing one norgestrel 0.075 mg progestogen-only pill. Study designIn a prospective, two-site, randomized, crossover study, healthy women aged 18 to 35 with BMI <32.0 kg/m² and regular ovulatory cycles completed a baseline 28-day cycle with correct daily pill use followed by two intervention cycles in which, around mid-cycle, one pill was taken 6 hours late or missed completely. We undertook ovarian ultrasonography, estradiol and progesterone measurement, and cervical mucus assessments every 3 to 4 days (daily around the time of the incorrect use) and based the theoretical contraceptive protection score on ovarian activity status, cervical mucus and their temporal relationship. ResultsOf 91 potential participants screened, 52 started the study and 46 provided complete data for each intervention cycle. Fourteen participants (30%) ovulated in each of the two intervention cycles, with four during the delayed pill cycle and two during the missed pill cycle having an abnormal luteal phase. Seven participants in the delayed pill cycle, and six with a missed pill had elevated cervical mucus scores temporally associated with the intervention. However only two women, one in the delayed pill cycle and one in the missed pill cycle, had cervical mucus scores in the range considered favorable for fertility. ConclusionsDelayed or missed intake of a single norgestrel 0.075 mg progestogen-only pill appears to have little effect on theoretical contraceptive efficacy. ImplicationsThis biomedical study suggests that taking a norgestrel 0.075mg progestogen-only pill 6 hours late or missing one pill have little effect on ovarian activity or cervical mucus and may not jeopardize contraceptive efficacy. Correlation with typical use outcomes is necessary to confirm pregnancy risk with delayed or missed norgestrel intake.

Impact of Time-Restricted Feeding on Adaptation to a 6-Hour Delay Phase Shift or a 12-Hour Phase Shift in Mice.

Nowadays, more and more people are suffering from circadian disruption. However, there is no well-accepted treatment. Recently, time-restricted feeding (TRF) was proposed as a potential non-drug intervention to alleviate jet lag in mice, especially in mice treated with a 6-h advanced phase shift. Here, we challenged C57BL/6 mice with a 6-h delay phase shift or a 12-h shift (day-night reversal) combined with 6- or 12-h TRF within the dark phase and found the beneficial effects of given TRF strategies in certain phase-shifting situations. Although behavioral fitness did not correlate well with health status, none of the TRF strategies we used deteriorated lipopolysaccharide-induced sepsis. These findings improve our understanding of the benefits of TRF for adaptation to circadian disruption.

Inhibition of the ventral midline thalamus does not alter encoding, short-term holding or retrieval of spatial information in rats performing a water-escape working memory task

Working memory (WM) is a function operating in three successive phases: encoding (sample trial), holding (delay), and retrieval (test trial) of information. Studies point to a possible implication of the thalamic reuniens nucleus (Re) in spatial WM (SWM). In which of the aforementioned 3 phases the Re has a function is largely unknown. Recently, in a delayed SWM water-escape task, we found that performance during the retrieval trial correlated positively with c-Fos expression in the Re nucleus, suggesting participation in retrieval. Here, we used the same task and muscimol (MUSC) inhibition or DREADD(hM4Di)-mediated inhibition of the Re during information encoding, right thereafter (thereby affecting the holding phase), or during the retrieval trial. A 6-hour delay separated encoding from retrieval. Concerning SWM, MUSC in the Re nucleus did not alter performance, be it during or after encoding, or during evaluation. CNO administered before encoding in DREADD-expressing rats was also ineffective, although CNO-induced inhibition disrupted set shifting performance, as found previously (Quet et al., Brain Struct Function 225, 2020), thereby validating DREADD efficiency. These findings are the first that do not support an implication of the Re nucleus in SWM. As most previous studies used T-maze alternation tasks, which carry high proactive interference risks, an important question to resolve now is whether the Re nucleus is required in (T-maze alternation) tasks using very short information-holding delays (seconds to minutes), and less so in other short-term spatial memory tasks with longer information holding intervals (hours) and therefore reduced interference risks.

Ventricular arrhythmias in patients with immune checkpoint inhibitor myocarditis

Abstract Background Immune checkpoint inhibitor (ICI)-associated myocarditis is associated with a markedly increased risk of morbidity and mortality. The occurrence of ventricular arrhythmias (VA) in patients with ICI-associated myocarditis has not been well characterized. Purpose The aim of this study was to determine the characteristics and risk factors for severe VA in patients with ICI myocarditis. Methods The cohort consisted of 202 patients with ICI myocarditis. Ventricular arrhythmias were defined as a composite of sustained ventricular tachycardia and ventricular fibrillation. We used a multivariable logistic regression model to test the association between clinical variables and the development of VA. Results From a cohort of 202 patients with ICI myocarditis (67±13 years, 35% female, 60% hypertension, 23% diabetes mellitus), 41 (20.3%) developed VA, of which, 33 had VT and 8 had VF. The median time from admission to VF was 144 hours and to VT was 72 hours. A VA occurred in 17.5% of patients with a normal LVEF, and 25% of patients with reduced LVEF. On univariate analysis, a QRS duration &amp;gt;110ms (OR 2.88, 95% CI 1.40 to 6.16, P=0.005) and a QTc duration &amp;gt;470ms were associated with an increased probability of VA (OR 2.58, 95% CI 1.23, 5.41, P=0.012). The association remained significant after adjustment for age and gender. Additionally, a longer time from admission to initiation of corticosteroids was associated with a higher probability of VA (OR 1.06, 95% CI 1.01 to 1.13, P=0.027). The association between the time from admission to administration of corticosteroids and probability of VA remained significant after adjustment for age, gender, and LVEF on admission (OR, 1.06, 95% CI 1.00, 1.13, P=0.037) where each 6-hour delay in the initiation of corticosteroids was associated with a 4% increase in the risk for VA. Conclusions Ventricular arrhythmias are common in the setting of ICI myocarditis and are observed in patients presenting with both a preserved and a reduced LVEF. Wider QRS and longer QT at presentation and longer time from admission to initiation of corticosteroids were associated with an increased risk of VA. Funding Acknowledgement Type of funding sources: None.

Timing of tracheal intubation on mortality and duration of mechanical ventilation in critically ill children: A propensity score analysis.

We aimed to investigate whether early tracheal intubation (TI) is associated with a reduced risk of mortality and increased ventilator-free days (VFD). We performed a retrospective cohort study of children 0 to 18 years old in a pediatric intensive care unit (PICU), between 2008 and 2017. Patient demographics, vital signs, and laboratory findings were extracted. Using a time-dependent propensity score-matched algorithm, each patient was matched with another equally likely to be intubated within the same hour but was actually intubated with ≤2 hours, 2 to 4 hours, and 4 to 6 hoursdelays. Outcomes were mortality and VFD. Among 333 patients, the median age was 1.72 years (interquartile range [IQR] 0.17-7.75). Thirty children died (9.0%) and the median PICU length of stay was 6.7 days (IQR 3.9-13.2). Early TI did not decrease mortality significantly when compared to a ≤2 hour delay (odds ratios [OR] 0.86; 95% CI, 0.40-1.85), a 2 to 4 hour delay (OR, 0.81; 95% CI, 0.39-1.69), or a 4 to 6 hour delay (OR, 0.87; 95% CI, 0.43-1.79). Similarly, early TI did not significantly increase VFD. Patients with early TI had 0.09 more VFD (95% CI -1.83 to 2.01) when compared to a delay within 2 hours, 0.23 more VFD (95% CI -1.66 to 2.13) when compared to a 2 to 4-hour delay and 0.56 more VFD (95% CI -1.49-2.61) when compared to a 4 to 6-hour delay. We did not find a significant association between the timing of TI and mortality or VFD in critically ill children.

The Emergency Department's Impact on Inpatient Critical Care Resources.

Critical care is an expensive and limited resource in the United States. Estimates from more than a decade ago suggest that over $100 billion a year is spent on critical care services.1 Over the past two decades, the number of patients presenting to the Emergency Department (ED) requiring critical care services has increased at a much higher rate than the growth in overall ED volume.2,3 The proportion of ED patients requiring Intensive Care Unit (ICU) admission has increased 75% over the first decade of the twenty-first century. In addition to the increase in the absolute number of patients requiring critical care admission, the ED length of stay for critically ill patients increased by 60 minutes. This resulted in a total nationwide increase in critical care provided in the ED by more than threefold. This disproportionate increase in critical care time reflects both the increase in critical care volume and the increase in ED boarding of critically ill patients. Data from 2008 reported the median boarding time for a patient waiting in the ED for an ICU bed was more than 5 hours, and 30% of patients waited more than 6 hours for an ICU bed.2,3 This article is protected by copyright. All rights reserved.

Are open mandibular fractures still an emergency?

Early surgical management is often advocated for fractures of the tooth-bearing portion of the mandible. A 6-hour delay has been mentioned for the fixation of these fractures. Our aim was to bring this paradigm into question. All patients referred to our department from September 2012 to May 2014 for fractures of the tooth-bearing portion of the mandible were retrospectively included. For each patient, age, gender, aetiology of the fracture, and characteristics of the fractures were recorded. Tobacco and/or alcohol addictions, diabetes and mandibular dental condition were taken into account. We also noticed the preoperative delay and the occurrence of complications such as: haematoma, infection, wound dehiscence, osteosynthesis failure and pseudarthrosis. Among the 47 patients referred, 36 were treated with a delay of more than 6 hours (76.6%). In 88.8% of the cases, the reason for this delay was unavoidable. The mean delay time from trauma to surgery was 52 hours (range: 7-312). Forty-nine percent of the patients had comorbidities. Complications occurred in 6 patients leading to an overall complication rate of 16.67%. A statistically significant higher complication rate was observed among smokers (P=0.006). No statistical relationship was found between the delay and the occurrence of complications (P=0.994). This study suggests that fractures of the tooth-bearing portion of the mandible should no longer be considered as an emergency that must be treated within a 6-hour delay.

Mechanical Tissue Resuscitation at the Site of Traumatic Brain Injuries Reduces the Volume of Injury and Hemorrhage in a Swine Model

Traumatic brain injuries (TBIs) continue to be a devastating problem with limited treatment options. Previous research applying controlled vacuum to TBI in a rat model resulted in smaller injuries and more rapid recovery. To examine the effects of the application of a controlled vacuum (mechanical tissue resuscitation) to TBI in a large-animal model. The magnitude of vacuum, length of application, and length of delay between injury and the application of mechanical tissue resuscitation were investigated. Localized, controlled cortical injuries were created in swine. Vacuums of -50 and -100 mm Hg were compared. Mechanical tissue resuscitation for 3 or 5 days was compared. Delays of 0, 3, or 6 hours between the creation of the TBI and the initiation of mechanical tissue resuscitation were examined. Analysis included histological assessments, computed tomographic perfusion, and magnetic resonance imaging (T2, proton magnetic spectra). A -100 mm Hg vacuum resulted in significantly smaller mean contused brain and hemorrhage volumes compared with -50 mm Hg and controls. Magnetic resonance spectra of treated animals returned to near baseline values. All 10 animals with 5-day mechanical tissue resuscitation treatment survived. Three of 6 animals treated for 3 days died after the discontinuation of treatment. A 3-hour delay resulted in similar results as immediate treatment. A 6-hour delay produced significant, but lesser responses. Application of mechanical tissue resuscitation to TBI was efficacious in the large-animal model. Application of -100 mm Hg for 5 days resulted in significantly improved outcomes. Delays of up to 3 hours between injury and the initiation of treatment did not diminish the efficacy of the mechanical tissue resuscitation treatment.

Delayed clinical and ex vivo response to mammalian meat in patients with IgE to galactose-alpha-1,3-galactose

In 2009, we reported a novel form of delayed anaphylaxis to red meat related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Although patients were remarkably consistent in their description of a 3- to 6-hour delay between eating mammalian meat and the appearance of symptoms, this delay has not been demonstrated under observed studies. We sought to formally document the time course of clinical symptoms after the ingestion of mammalian meat in subjects with IgE to alpha-gal and to monitor ex vivo for the appearance of markers of an allergic reaction. Open food challenges were performed with mammalian meat in 12 subjects with a history of severe urticarial reactions 3 to 6 hours after eating beef, pork, or lamb, as well as in 13 control subjects. Blood samples were taken hourly during each challenge. Ten of 12 subjects with IgE to alpha-gal had clinical evidence of a reaction during the food challenge (vs none of the control subjects, P < .001). The reactions occurred 3 to 7 hours after the initial ingestion of mammalian meat and ranged from urticaria to anaphylaxis. Tryptase levels were positive in 3 challenges. Basophil activation, as measured by increased expression of CD63, correlated with the appearance of clinical symptoms. The results presented provide clear evidence of an IgE-mediated food allergy that occurs several hours after ingestion of the inciting allergen. Moreover, here we report that in vivo basophil activation during a food challenge occurs in the same time frame as clinical symptoms and likely reflects the appearance of the antigen in the bloodstream.

Forced Desynchronization of Activity Rhythms in a Model of Chronic Jet Lag in Mice

We studied locomotor activity rhythms of C57/Bl6 mice under a chronic jet lag (CJL) protocol (ChrA(6/2) ), which consisted of 6-hour phase advances of the light-dark schedule (LD) every 2 days. Through periodogram analysis, we found 2 components of the activity rhythm: a short-period component (21.01 ± 0.04 h) that was entrained by the LD schedule and a long-period component (24.68 ± 0.26 h). We developed a mathematical model comprising 2 coupled circadian oscillators that was tested experimentally with different CJL schedules. Our simulations suggested that under CJL, the system behaves as if it were under a zeitgeber with a period determined by (24 - [phase shift size/days between shifts]). Desynchronization within the system arises according to whether this effective zeitgeber is inside or outside the range of entrainment of the oscillators. In this sense, ChrA(6/2) is interpreted as a (24 - 6/2 = 21 h) zeitgeber, and simulations predicted the behavior of mice under other CJL schedules with an effective 21-hour zeitgeber. Animals studied under an asymmetric T = 21 h zeitgeber (carried out by a 3-hour shortening of every dark phase) showed 2 activity components as observed under ChrA(6/2): an entrained short-period (21.01 ± 0.03 h) and a long-period component (23.93 ± 0.31 h). Internal desynchronization was lost when mice were subjected to 9-hour advances every 3 days, a possibility also contemplated by the simulations. Simulations also predicted that desynchronization should be less prevalent under delaying than under advancing CJL. Indeed, most mice subjected to 6-hour delay shifts every 2 days (an effective 27-hour zeitgeber) displayed a single entrained activity component (26.92 ± 0.11 h). Our results demonstrate that the disruption provoked by CJL schedules is not dependent on the phase-shift magnitude or the frequency of the shifts separately but on the combination of both, through its ratio and additionally on their absolute values. In this study, we present a novel model of forced desynchronization in mice under a specific CJL schedule; in addition, our model provides theoretical tools for the evaluation of circadian disruption under CJL conditions that are currently used in circadian research.

Treatment of Oral Squamous Cell Carcinoma with Accelerated Radiation Therapy and Concomitant Carboplatin in Cats

Feline oral squamous cell carcinoma (SCC) carries a very poor prognosis with traditional treatments. To examine the effectiveness of adding carboplatin to a previously published accelerated radiation protocol in the treatments of oral SCC in cats. Thirty-one cases of oral SCC in cats. Tumor sites included lingual (n = 9), mandible (n = 10), maxilla (n = 7), tonsil (n = 4), and cheek (n = 1). Prospective trial using a planned radiation protocol consisting of 14 fractions of 3.5 Gy given within a 9-day period with the addition of carboplatin given at 90-100 mg/m(2) on day 1 and day 4.5. Treatments were twice daily with a 6-hour delay between treatments. All cats presenting with oral SCC without evidence of distant metastasis were eligible. Median survival for all cats was 163 days (range 53-770 days) with a mean of 319 ± 53 days with significant predictors of survival being site (P = .004) and whether there was a complete response at 30 days (P = .001). Cats with tumors of tonsil origin or cheek responded best to therapy and were long-term survivors with a mean survival of 724 days and the median had not been reached because of continued survival of 4 cats. This protocol offers an aggressive yet tolerable treatment of oral SCC in cats that might offer improved survival as compared with previously reported treatments. The long-term survival of cats with tonsillar SCC has not been reported previously.

8 EFFECT OF SEMEN TYPES (SEXED v. NONSEXED) ON CONCEPTION RATES OF GIROLANDO HEIFERS INSEMINATED IN FIXED-TIME AI

With the goal of optimizing protocols, fixed-time artificial insemination (FTAI) was performed under field conditions in a study to evaluate conception rates in Girolando (5/8) heifers (18 to 24 months of age) treated with estradiol benzoate (BE) to induce ovulation. Forty heifers were allocated to 2 groups with 20 animals each: GI-sexed semen (2 million spermatozoa/dose) and GII-nonsexed semen (20 million spermatozoa/dose), with body condition score (BCS) of 3.0 ± 0.14 (scale of 1 to 5), middleweight of 335 ± 38 kg, so that it was made for reutilization of progesterone device. On Day 0 (morning), the animals received 2.0 mg of BE (RIC-BE®,Tecnopec, São Paulo, Brazil), 0.075 mg of D-cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina), and an intravaginal device of 1 g of progesterone (Primer®, Tecnopec). On Day 8 (morning) the device was removed and 0.075 mg of D-cloprostenol was managed in the GI animals, then these animals received 1.0 mg of BE 24 h after device removal. The insemination was in the late afternoon of Day 10 with a 6-hour delay (4 to 6 pm). The GII animals received Primer previously used for 8 days (being used in the GI animals under the same protocol). After pregnancy diagnosis at 60 days, a third group was created (GIII) using the not-pregnant animals of GI and GII. In GIII, Primer from third use [disinfected in solution Kilol®-L 1:250 (Quinabra, São Paulo, Brazil) and rinsed with water, dried, and packed in plastic sacks and kept for 60 days] was used following the GI protocol with sexed semen. There were no significant differences (P &gt; 0.05) in the conception rates of 40, 58, and 65% among groups GI (8/20), GII (11/20), and GIII (13/20). These results indicate very good conception rates for heifers, contrary to recommendations of commercial companies of sexed semen that alert for the conception rate for mated animals to be lower when using FTAI and mating protocols in mass, compared with that of AI after estrus observation.

Regulation of Retinal Photoreceptor Phagocytosis in a Diurnal Mammal by Circadian Clocks and Ambient Lighting

To characterize light and circadian control of photoreceptor phagocytosis in a diurnal cone-rich rodent. Diurnal Arvicanthis ansorgei were maintained under standard cyclic light (12 hours 300 lux white light [L]/12 hours dark [D]) and were divided into five groups: 1, maintained in LD; 2, transferred to constant darkness (DD); 3, transferred to constant light (LL, 300 lux); 4, subjected to 6-hour advance in light onset; and 5, subjected to 6-hour delay in light onset. Animals were killed every 3 hours during 24 hours, and their eyes were rapidly enucleated and fixed. Cryosections were stained using specific rod (rhodopsin) and cone (MW cone opsin) antibodies. Immunopositive inclusions within the retinal pigment epithelium layer were quantified for each time point. In LD, both rod and cone phagocytosis showed coincident synchronized profiles with sharp peaks 1 to 2 hours after light onset. In groups 2 and 3, phagocytic activity shifted partially to the new light schedules. In DD, the temporal phagocytic profile resembled largely that of LD. On the contrary, LL animals exhibited large alterations in both rod and cone phagocytosis. There was no longer any peak, with both showing relatively uniform profiles. In addition, the number of cone phagosomes was much higher ( approximately 250% increase) compared with LD or DD. These data are the first to measure photoreceptor phagocytosis in a diurnal mammal under different lighting conditions and to highlight the disruptive effects of constant light, especially on cone photoreceptor function.

Behavioral recovery from traumatic brain injury after membrane reconstruction using polyethylene glycol

Polyethylene glycol (PEG; 2000 MW, 30% by volume) has been shown to mechanically repair damaged cellular membranes and reduce secondary axotomy after traumatic brain and spinal cord injury (TBI and SCI respectively). This repair is achieved following spontaneous reassembly of cell membranes made possible by the action of targeted hydrophilic polymers which first seal the compromised portion of the plasmalemma, and secondarily, allow the lipidic core of the compromised membranes to resolve into each other. Here we compared PEG-treated to untreated rats using a computer-managed open-field behavioral test subsequent to a standardized brain injury. Animals were evaluated after a 2-, 4-, and 6-hour delay in treatment after TBI. Treated animals receive a single subcutaneous injection of PEG. When treated within 2 hours of the injury, injured PEG-treated rats showed statistically significant improvement in their exploratory behavior recorded in the activity box when compared to untreated but brain-injured controls. A delay of 4 hours reduced this level of achievement, but a statistically significant improvement due to PEG injection was still clearly evident in most outcome measures compared at the various evaluation times. A further delay of 2 more hours, however, eradicated the beneficial effects of PEG injection as revealed using this behavioral assessment. Thus, there appears to be a critical window of time in which PEG administration after TBI can provide neuroprotection resulting in an enhanced functional recovery. As is often seen in clinically applied acute treatments for trauma, the earlier the intervention can be applied, the better the outcome.

Alterations in Circadian Rhythm Phase Shifting Ability in Rats Following Ethanol Exposure During the Third Trimester Brain Growth Spurt

Disruptions in sleep and feeding rhythms are among the consequences of prenatal alcohol exposure. Previously, we reported that ethanol exposure during the second trimester equivalent in rats produces long-lasting impairments in circadian system functioning. In the present study, we examined the effects of ethanol exposure during the third trimester equivalent brain growth spurt on the development of the circadian clock system. Sprague-Dawley male rat pups were exposed to 6.0 g/kg/d ethanol via an artificial rearing procedure on postnatal days (PD) 4 through 9 (EtOH). An artificially reared gastrostomized control group and a normally reared suckle control group were also included. At 10 to 12 weeks of age, wheel-running behavior was measured continuously under a 12-hour/12-hour light/dark (LD) cycle. Thereafter, subjects were exposed to a 6-hour phase delay of the LD cycle, and the ability to adjust to the new LD cycle was evaluated. Before the phase delay, onset time of activity and acrophases of activity in all 3 groups were not significantly different from one another. After the 6-hour LD cycle delay, EtOH subjects were slower to adapt to the new cycle compared with both control groups, as measured by both activity onset and acrophase. Throughout the experiment, activity levels of EtOH subjects tended to be higher compared to both controls. These data demonstrate that ethanol exposure during the third trimester disrupts the ability to synchronize circadian rhythm to light cues. Disruptions in circadian regulation may cause abnormal behavioral rhythmicity, such as disrupted sleep and feeding patterns, as seen in individuals prenatally exposed to ethanol.

Proteome analysis and functional expression identify mortalin as an antiapoptotic gene induced by elevation of [Na+]i/[K+]i ratio in cultured vascular smooth muscle cells.

Apoptosis of vascular smooth muscle cells (VSMCs) plays an important role in remodeling of vessel walls, one of the major determinants of long-term blood pressure elevation and an independent risk factor for cardiovascular morbidity and mortality. Recently, we have found that apoptosis in cultured VSMCs can be inhibited by inversion of the intracellular [Na+]/[K+] ratio after the sustained blockage of the Na+,K+-ATPase by ouabain. To understand the mechanism of ouabain action, we analyzed subsets of hydrophilic and hydrophobic VSMC proteins from control and ouabain-treated cells by 2-dimensional electrophoresis. Ouabain treatment led to overexpression of numerous soluble and hydrophobic cellular proteins. Among proteins that showed the highest level of ouabain-induced expression, we identified mortalin (also known as GRP75 or PBP-74), a member of the heat shock protein 70 (HSP70) superfamily and a marker for cellular mortal and immortal phenotypes. Northern and Western blotting and immunocytochemistry all have confirmed that treatment of VSMCs with ouabain results in potent induction of mortalin expression. Transient transfection of cells with mortalin cDNA led to at least a 6-hour delay in the development of apoptosis after serum deprivation. The expression of tumor suppressor gene, p53, in mortalin-transfected cells was delayed to the same extent, and the expressed protein showed abnormal perinuclear distribution, suggesting that p53 is retained and inactivated by mortalin. Our studies therefore define a new [Na+]i/[K+]i-responsive signaling pathway that may play an important role in the regulation of programmed cell death in VSMCs.

The enhancement of endogenous cAMP with pituitary adenylate cyclase-activating polypeptide protects rat kidney against ischemia through the modulation of inflammatory response.

Cyclic nucleotide analogue administration improves ischemia-reperfusion damage in several organs. The neuropeptide pituitary adenylate cyclase-activating polypeptide, PACAP-38, is a potent stimulus to enhance cellular cAMP levels. This study tested the protective effect of enhancing endogenous cAMP levels by PACAP-38 in a model of warm renal ischemia. Sprague-Dawley rats underwent 40 min of bilateral warm renal ischemia. PACAP-38 continuous infusion began either before ischemia or at 6 hr or 18 hr after ischemia. A mini-osmotic pump infused PACAP-38 throughout 7 days of follow-up. Groups were constructed with sham, ischemic control, and dibutyryl cAMP treated animals, and four PACAP-38 treatment groups, using 16 pmol/hr or 160 pmol/hr of the compound, or delaying its administration by 6 hr or 18 hr after ischemia. Renal function was assessed by means of serum creatinine levels on days 1, 2, 3, and 7 after ischemia. Conventional histology was performed on day 7. Renal myeloperoxidase (MPO) activity, infiltrating CD45+ cells, plasma and tissue cAMP, and serum IL-6 were measured. Continuous administration of the high concentration of PACAP-38 ameliorated renal function and morphologic abnormalities induced by warm ischemia. Treatment with dibutyryl cAMP produced morphologic protection but only partial functional effect on the ischemic kidney. A 6-hour delay in the administration of the compound after ischemia offered similar protective effect, whereas an 18-hr delay did not. The neuropeptide clearly increased circulating cAMP after ischemia but not cAMP in renal tissue. PACAP-38 increased circulating IL-6, and minimized renal inflammatory cell infiltration induced by ischemia-reperfusion injury, as evidenced by a reduction of MPO activity and the number of CD45+ cells in ischemic renal tissue. Enhancement of endogenous circulating cAMP with PACAP-38 modulates postischemic inflammatory response and strongly protects from ischemic acute renal failure, even when administration is delayed for 6 hr after injury.