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Antarctic sea ice plays a pivotal role in the global climate system. Forming a highly reflective,dynamic, and insulative blanket that varies seasonally in its areal coverage from ~3 × 106 km2to ~19–20 × 106 km2, sea ice and its snow cover strongly modifies ocean–atmosphere fluxes andinteraction processes (Bourassa et al. 2013). Moreover, brine rejection into the underlying oceanduring sea ice formation onsome continental shelf areasleads to the formationof Antarctic Bottom Waterthat contributes to the globalocean overturning circulation(Johnson 2008). Antarcticsea ice also acts as a protectivebuffer for ice shelvesagainst destructive oceanswells (Massom et al. 2018)and modulates the interactionof warm ocean waterswith ice shelf basal cavitiesto affect basal melt there(Timmermann and Hellmer2013). Finally, it also formsa key habitat for a myriad ofbiota—ranging from microorganismsto whales (Thomas2017)—that are strongly affectedby changes in the presenceand seasonal rhythms ofthe sea ice cover (e.g., Massomand Stammerjohn 2010).

Studies typically measure mood changes during smoking cessation treatment in two ways: (a) by tracking mean change in depression scores or (b) by tracking the incidence of major depression development using diagnostic assessments. However, tracking mean change does not capture variability in individual mood trajectories, and diagnosing participants at multiple time points is time and labor intensive. The current study proposes a method of assessing meaningful increases in depression without the use of diagnostic assessments by utilizing reliable and clinically significant change criteria. This method was applied to 212 participants in a smoking cessation trial to explore the relationship between smoking status and depressed mood, assessed at baseline, end-of-treatment, and 2-, 6-, and 12-month follow-ups. High rates of reliable (24-28%) and both reliable and clinically significant increases (23-24%) in depressed mood were observed across all participants, regardless of whether or not they achieved abstinence. However, when we calculated group mean change in depression during the trial, only decreases in depressed mood where observed across several intervals. Findings indicate that utilizing reliable and clinically significant change criteria to track symptoms of depression during smoking cessation treatment leads to different conclusions than simply tracking mean changes. We propose that a combination of reliable and clinically significant change criteria may serve as a useful proxy measure for the development of major depressive disorder during smoking cessation.

Objective No studies have examined the relationship between caregiver beliefs about the risks of smoking to their own health and caregiver beliefs about the effect of their smoking on their child's health. In the current study, we investigated our proposed risk congruence hypothesis among caregivers who smoke. Specifically, we investigated whether caregivers' self-perceived risk of smoking is directly associated with their perception of the risks of smoking to their child. Method The sample consisted of 271 regular smokers (≥ 3 cigarettes per day; Mage = 32.9 years; 214 women) who were caregivers of children with asthma (Mage = 4.9 years) who had a recent visit to the emergency room for their asthma. Three constructs of perceived risk were measured via self-report questionnaires assessing both caregiver perception of smoking risk to self and to child: Precaution Effectiveness, Optimistic Bias, and Perceived Vulnerability. Child asthma-related functional morbidity and home and child secondhand smoke exposure were also assessed. Results Consistent with our risk congruence hypothesis, self-perceived risk of smoking was significantly associated with perceived risk to child, over and above the child's secondhand smoke exposure and caregiver report of child's asthma symptoms (i.e., asthma-related functional morbidity). Conclusions These findings should be considered in the design of clinical interventions seeking to influence risk of caregiver behavior on child health.

Stress analysis by FLIR (forward-looking infrared) evaluation (SAFE) has been demonstrated to monitor sweat pore activation (SPA) as a novel surrogate measure of sympathetic nervous system (SNS) activity in a normal population. SNS responses to a series of 15 1-s, 82 dB, white noise bursts were measured by skin conductance (SC) and SAFE monitoring of SPA on the fingers (FiP) and face (FaP) in 10 participants with posttraumatic stress disorder (PTSD) and 16 trauma-exposed participants without PTSD (M(age) = 48.92 ± 12.00 years; 26.9% female). Within participants, SC and FiP responses across trials were strongly correlated (r = .92, p < .001). Correlations between SC and FaP (r = .76, p = .001) and between FiP and FaP (r = .47, p = .005) were smaller. The habituation of SNS responses across the 15 trials was substantial (SC: d = −2.97; FiP: d = −2.34; FaP: d = −1.02). There was a strong correlation between habituation effects for SC and FiP (r = .76, p < .001), but not for SC and FaP (r = .15, p = .45) or FiP and FaP (r = .29, p = .16). Participants with PTSD showed larger SNS responses to the first loud noise than those without PTSD. PTSD reexperiencing symptoms assessed by the PTSD Checklist on the day of testing were associated with the SNS responses to the first loud noise measured by SC (d = 1.19) and FiP (d = .99), but not FaP (d = .10). This study confirms convergence of SAFE and SC as valid measures of SNS activity. SAFE FiP and SC responses were highly predictive of self-rated PTSD reexperiencing symptoms. SAFE may offer an attractive alternative for applications in PTSD and similar populations.

The Healthy Bladder Program was developed as part of an academic and health care partnership and was designed specifically for older adults residing in independent and assisted living. Program content was based on best practices that can be used by nursing staff to provide information about promoting and maintaining bladder health. One hundred eighty older adults, recruited from long-term care retirement communities, attended the 1-hour program. Findings showed that the program was successful in providing bladder health information that older adults could use immediately; suggestions are given for best practice applications.

The successful irrigation of potatoes requires a knowledge of both irrigation application and scheduling methods. A four-year field study of four irrigation scheduling and application methods for Russet Burbank potatoes was undertaken on a sandy loam soil near Oakes, North Dakota. A randomized complete block statistical design was used to assess the influence of irrigation treatments on total yield, no. 1 grade yield, specific gravity, and total irrigation applied. For the reference treatment, above-ground drip irrigation (AGDI) was used to apply irrigations based on 40% depletion of root zone available water on an area basis. The other treatments were: (1) AGDI, basing scheduling on a crop water stress index (CWSI) of 0.2; (2) subsurface drip irrigation (SDI), basing scheduling on measured soil matric potentials (SMPs) of 30 kPa using a feedback and control system to automate irrigation applications; and (3) AGDI, basing scheduling on SUBSTOR-Potatoes (SUBSTOR) growth model estimates of water use. Because of high relative humidity and intermittent cloudiness, irrigations for the CWSI treatment were also scheduled based on SMP of 30 kPa at 0.3-m depth. Averages for yield (39.7 Mg ha–1), percentage no. 1 grade (76.1%), and specific gravity (1.086) did not differ between treatments. The reference treatment required an average of 220 mm irrigation water each year, significantly higher than the 167 mm for CWSI , the 129 mm for SDI, and the 149 mm for SUBSTOR. Improved irrigation methods can save water without compromising potato yield or quality. Tensiometer-based methods were preferred, while SUBSTOR has limited practicality for irrigation scheduling.

Irrigation of popcorn requires knowledge of methods of applying and scheduling irrigations. A four-year field plot study of four application-scheduling methods for popcorn was undertaken on a sandy loam soil near Oakes, North Dakota (ND), using a randomized block design. The study was designed to assess the influence of the methods on grain yields, popped volumes, and total irrigation water amounts applied for “White Cloud” popcorn. The reference method used aboveground drip irrigation (AGDI) to apply water and a scheduling method based on estimates of when 40% depletion of root zone available water (40% D) would be reached. The other irrigation application-scheduling methods were: AGDI and scheduling based on plant temperature, i.e., crop water stress index (CWSI) of 0.4; subsurface drip irrigation (SDI) and scheduling based on measured soil matric potential (SMP) of 30 kPa using a feedback and control system to automate irrigation applications through an SDI system; and AGDI and CERES-Maize (CM) growth model estimates of water use. Due to difficulties in implementing the CWSI method (high relative humidity and intermittent cloudiness), irrigations were also scheduled based on tensiometer-measured SMP of 40 kPa at 0.3-m depth for the CWSI treatment. Compared to the 40% D method, all other methods achieved statistically significant (0.05 level) irrigation water savings for popcorn without significant reductions in yields or popped volumes. Four-year average irrigation water amounts were 235, 134, 142, and 156 mm for the 40% D, CWSI, SDI, and CM methods, respectively, with corresponding popcorn yields of 4.63, 4.33, 4.44, and 4.47 Mg ha–1 and popped volumes of 26.3, 28.0, 28.3, and 28.0 L kg–1.

Subsurface drip irrigation (SDI) systems offer advantages over other types of irrigation systems for specialty crop production, including water savings, improved trafficability, and a drier canopy. This study was conducted to evaluate the performance of SDI, placed at 1.2-m (4-ft) lateral spacing and buried at 0.28-m (11-in.) depth, in a subhumid climate with severe winters. Effects on crop yield and crop quality of tape design (from five manufacturers) and position along 152-m (500-ft) lateral runs were investigated for three consecutive years on a sandy loam soil near Oakes, N. Dakota. In 1993, marketable and total sweet corn yields averaged 13.9 and 14.9 Mg ha–1 (6.20 ton ac–1 and 6.65 ton ac–1), respectively. In 1994, U.S. No. 1, U.S. No. 2, and total yields for winter squash were 17.7, 6.8, and 31.9 Mg ha–1 (7.90, 3.03, and 14.23 ton ac–1), respectively. In 1995, the cabbage yield averaged 98 Mg ha–1 (43.7 ton ac–1). Yields were measured at three transects [approximately 17, 76, and 136 m (56 ft, 250 ft, and 446 ft) from the upstream ends of the drip laterals] to determine effects of tape design on water distribution and corresponding yield. Yields did not differ statistically between designs for any transect in any year. Measured emitter discharge rates decreased dramatically with distance downstream from the start of the tape. This was attributed to friction losses in the tape, deformation of the normally circular cross-section of the tape by winter conditions, soil compaction from tillage operations, and calcium deposits. Subsurface drip irrigation tape appears durable enough to withstand winters in the northern Great Plains for multiple-season use, provided proper installation and maintenance procedures are followed.

Irrigation scheduling for corn requires knowledge of methods for timing irrigation applications. A three-year field plot study of irrigation scheduling methods for corn was undertaken on a sandy loam soil near Oakes, North Dakota, using a randomized block design. The study was designed to assess the influence of the methods on grain yields and total irrigation amounts applied. The reference irrigation timing method was based on allowable root zone available water depletion (40%). The other irrigation timing methods used were: partial evapotranspiration (ET) (0.5 ¥ ET) replacement, crop water stress index (CWSI of 0.2, 0.4, and 0.6), measured soil matric potential (30 and 50 kPa), and growth model (CERES-Maize) estimates of dry matter accumulation and water use. In terms of crop yield per unit ET, the best method was the 50-kPa treatment. The 50-kPa method resulted in the maximum average yield of 12 200 kg ha–1 while achieving a statistically significant average reduction of 139 mm (40%) in irrigation application compared to the reference treatment. The nonreference methods, except for CWSI = 0.6, appear to offer the potential for significant irrigation water savings without significant yield reductions. The 0.6 CWSI treatment suffered a statistically significant yield reduction of 1 600 kg ha–1 (13%).

Experiments were conducted to determine if both electrical and chemical stimulation of the ventromedial hypathalamic nucleus (VMH) could activate brown adipose tissue (BAT) thermogenesis. Age-matched, room-acclimated (21 °C) and cold-acclimated (4 °C for 3 weeks prior to testing) male Sprague-Dawley rats were given unilateral electrical or chemical stimulation to the VMH by way of a ‘chemotrode apparatus’. The devised ‘chemotrode’ allowed both electrical stimulation (insulated piano wire stimulating electrode) and chemical stimulation (23 gauge stainless steel intracranial cannula of equal length) to be performed at the same VMH site using a common 19 gauge stainless steel outer guide tube. The first unilateral VMH electrical stimulation (0.5 ms pulse, 50 Hz and 120 μA for 30 s) caused no significant rise in interscapular brown adipose tissue temperature (Tbat) colonic (Tc) or tail surface temperatures (Tt), compared to respective prestimulation control values in rats acclimated to 21 °C. In the 4 °C-acclimated group the first VMH electrical stimulation caused a significant rise in IBAT temperature.l-Glutamate administration to the same VMH site (60 nmol in 600 nl volume) also caused a significant increase in IBAT temperature in the 4 °C but not the 21 °C-acclimated rats. The rise in IBAT temperature following thel-glutamate injection to the 4 °C-acclimated group was similar to that found following the first electrical stimulation to this group. Interestingly, a second unilateral electrical stimulation of the VMH to 4 °C-acclimated rats could not evoke a similar increase in IBAT temperature suggesting that overalll-glutamate was acting in vivo as an excitotoxin. The results indicate that both unilateral chemical and electrical stimulation of the VMH of 4 °C but not 21 °C acclimated, anesthetized male Sprague-Dawley rats can evoke significant rises in IBAT temperature, indicative of activation of BAT thermogenesis by this CNS site. These results infer that cold acclimation causes facilitation of BAT thermogenesis peripherally and/or centrally such that subsequent electrical or chemical stimulation of the VMH can then evoke significant rises in IBAT temperature in those animals.

A case of lipoblastoma of mesentery in 13-month-old normally growing up boy was presented. During routine examination due to upper respiratory airways viral infection large abdominal tumor was found. Preoperative diagnostics let us establish its the most probable macro- and microscopic character and the tissue limits. Radical operation was performed. During the 5-month follow up period after the surgery there were not evident complications, we did not find any signs of tumor recurrence.

While many of your employees are likely to be an asset to your practice, some "loyal" employees aren't always what they seem. This article offers guidelines for physicians to guard against "loyalty" becoming a liability that hurts you, your staff, and your practice.

Experiments were conducted to determine (i) how naloxone administration alone could modify the inotropic (in electrically stimulated (ES) rat atria) and both the inotropic and chronotropic responses (in spontaneously beating (SB) rat atria) isolated from normotensive and hypotensive (hemorrhaged) rats, and (ii) how naloxone administration would modify the inotropic and chronotropic responses of isolated rat atria previously administered an opiate agonist (morphine), a muscarinic agonist (carbachol), or an α - and β-adrenergic agonist (noradrenaline). Naloxone (51–340 μM) added to ES atria caused a delayed but dose-related decrease in atrial tension (AT), whereas in SB atria, naloxone caused atrial heart rate (AHR) to fall and atrial tension (AT) to increase. Naloxone (68–340 μM), given to SB atria from acutely hypotensive rats, caused a similar increase in atrial tension as seen in the "normotensive" isolated (SB) atria and a similar decrease in atrial heart rate. Morphine sulphate (MS), 37–375 μM, administered to ES atria caused a delayed fall in AT, which was further decreased when naloxone (340 μM) was also added. In the SB atria, morphine caused a dose-related decrease in atrial heart rate whereas atrial tension increased. In SB preparations, atrial heart rate fell even further when naloxone was added to morphine compared with when morphine sulphate was given alone, whereas atrial tension was increased. Noradrenaline (3 or 12 μM) caused a positive, dose-related inotropic response in the ES atria, effects not influenced by the addition of naloxone. In the SB atria, naloxone caused no change in the dose-related increases in atrial tension and heart rate when combined with the lower dose of noradrenaline but decreased AT when combined with 12 μM noradrenaline, compared with when this dose of noradrenaline was given alone. Carbachol (683 nM – 1.37 μM) caused a dose-related decrease in atrial tension in ES atria, which was reversed completely by the addition of naloxone. In SB atria, carbachol decreased both atrial tension and heart rate, and with the addition of naloxone (340 μM), a further slight drop in atrial heart rate occurred, but concurrently, a marked rise in atrial tension was observed. The results indicate that naloxone can act with receptors directly within atrial tissue to cause changes in atrial tension and heart rate. The comparable delayed responses of morphine and naloxone suggest their effects are mediated by nonopiate receptors which, in time, cause decreases in calcium influx into the atria. The marked rise in atrial tension following naloxone administration in atria previously given carbachol suggest there is an interaction between naloxone- and carbachol-sensitive receptors in the atria. The net result of this interaction may again reflect a change (increase) in calcium influx into myocardial cells.Key words: rat atria, inotropy, chronotropy, morphine, carbachol, noradrenaline, acute hypotension.

Conscious, unrestrained rats were used to determine the hemodynamic (blood pressure and heart rate) responses following intravenous (IV) injection of dynorphin A(1–13) and the possible receptor mechanisms mediating those changes. Male Sprague-Dawley rats (300 g) were given IV bolus injections (via femoral venous catheter) of 6.0 to 600 nmoles/kg of dynorphin A(1–13), 8.0 nmoles/kg of norepinephrine HCl (NE), 14.3 pmoles/kg of angiotensin II or a vehicle control solution. Blood pressure (BP) and heart rate (HR) were monitored via femoral arterial catheter (into abdominal aorta) over 90 sec postpeptide or -amine administration before and 10 min after IV injection of 4.2 μmoles/kg of naloxone HCl (opiate antagonist), yohimbine HCl ( α 2 receptor antagonist) or prazosin HCl ( α 1 receptor antagonist). Dynorphin A(1–13) caused a transient but dose-related rise in mean arterial pressure (MAP) whereas mean pulse pressures (MPP) and mean heart rates (MHR) concomitantly fell, from preinjection control values in a dose-dependent fashion. Pretreatment with naloxone blocked the pressor response of only a subsequent injection with 20 nmoles/kg but not 60 nmoles/kg of dynorphin A or NE (8.0 nmoles/kg). Pretreatment with yohimbine suppressed the marked pressor responses of subsequent NE or Dyn A (60 nmoles/kg) administration whereas prazosin antagonized the rise in MAP of only the lower doses of dynorphin as well as NE. The suppression of the pressor responses of dynorphin by opiate or alpha receptor antagonists were not caused by tachyphylaxis for repeated injections of 6.0 or 60 nmoles/kg of dynorphin caused the same rise in MAP. The results indicate that an acute IV injection of dynorphin to conscious rats evokes a transient dose-related pressor response that is blocked by both opiate and alpha receptor antagonists, suggesting that its hypertensive effects may be due to an alpha receptor-mediated vasoconstrictor action.

The photochemistry and photophysics of tris(1,10-phenanthroline)chromium(III) ion, Cr(phen)/sub 3//sup 2 +/, following pulsed-laser excitation at 347 nm, have been studied in deaerated acidic and alkaline aqueous media (pH 3.0-11.1) at room temperature by using conductivity and visible optical detection methods. The lifetimes of the lowest doublet excited state(s) from which is derived the major portion of the photochemistry are little affected by changes in pH as monitored by emission and excited-state absorption nor are the initial intensity levels of these phenomena noticeably altered by pH changes. Alterations in pH do have significant effects on the conductivity signals, which correlate to photoaquation. Conductivity studies for natural pH (ca. pH 7.1) provide evidence for a ground-state intermediate with a pK/sub a/ value around 7. In basic media, an apparent single stage of conductivity occurs, and the values of the observed rate constant and the resulting overall change in conductance are dependent upon the concentration of hydroxide ion. The quantum yield for aquation at the highest pH of 11.1 is determined as 0.08 (+/-20%). By contrast, photochemical reaction in acidic media is found to be very much reduced relative to that occurring in alkaline solutions. A mechanism, incorporating a six-coordinate, monodentate phenathroline intermediate,more » is proposed, and it is used to discuss the occurrence of photoracemization and to compare the behavior of Cr(phen)/sub 3//sup 3 +/, where bpy designates the 2,2'-bipyridine ligand.« less

Experiments were designed using conscious Spargue–Dawley rats to determine the blood pressure (BP) and heart rate (HR) responses to intravenous doses of (1) the adrenal catecholamines noradrenaline (NA) and adrenaline (A), (2) adrenal pentapeptides methionine enkephalin (ME) and leucine enkephaline (LE), (3) combination (i.v.) injections of both ME or LE with NA or A that modulate the hemodynamic responses when the adrenal catecholamines were given alone, and (4) the possible receptor mechanisms mediating the resultant BP and HR response to i.v. pentapeptide administration. NA (0.48 and 2.4 nmol) and A (0.3 and 1.5 nmol) given i.v. evoked potent, dose-related pressor responses associated with reflex bradycardia. ME and LE (1.6 – 48 nmol) elicited transient (10–20 s) increases in mean arterial pressure (MAP), which was associated either with no change in mean heart rate (MHR), such as ME, or with slight bradycardia (i.e., LE). Combining ME or LE (16 nmol) with NA (2.4 nmol) or A (0.3 or 1.5 nmol) did not change MAP and MHR from when these respective doses of NA or A were given alone. However, 16 nmol of ME or LE with a low dose of NA (0.48 nmol) increased the pressor response compared with NA (0.48 nmol) given alone. Other experiments whereby specific receptor blockers (naloxone, diprenorphine, atropine, propranolol, phentolamine or quanethidine) were given i.v. 5 min before subsequent i.v. administration of LE or ME (16 nmol) indicated that only phentolamine or quanethidine could completely suppress the pressor responses of LE and ME. Naloxone and diprenorphine pretreatment attenuated the pressor response of LE but did not affect the BP response to ME. The results suggest that i.v. LE or ME injections to conscious rats evoke an α-adrenergic receptor-mediated pressor response which is not associated with tachycardia and that is likely due to vasoconstriction of the peripheral vasculature.

Hemodynamic (blood pressure and heart rate) responses of conscious drug-naive rats were studied following intravenous (i. v.) infusion of sterile saline, morphine sulphate, and then naloxone hydrochloride, as well as of other groups previously injected with morphine sulphate. Those groups chronically given morphine sulphate received twice daily injections of morphine sulphate (5 mg/kg, s.c. per injection) for 3 or 6 days before testing with the i. v. infusion of morphine sulphate. Drugs were infused (135 μL/min) through an indwelling femoral venous catheter via a Harvard infusion pump, and blood pressure was recorded from the abdominal aorta via a femoral arterial catheter. Other pretreatment studies were done to determine the receptor mechanisms mediating the blood pressure responses of drug-naive and chronic morphine-treated rats, whereby equimolar doses (0.32 μmol) of specific receptor antagonists were given as a bolus i.v. injection 5 min after saline but before subsequent infusion with morphine sulphate. Intravenous infusion of morphine sulphate (7.5 mg/kg total over 15 min) to drug-naive rats caused a transient but precipitous fall in mean arterial pressure and mean heart rate with an associated rise in mean pulse pressure; these effects were blocked in other groups pretreated with atropine. Interestingly, however, rats chronically injected with morphine sulphate for 3 days previously evoked a transient pressor response when subsequently infused i.v. with morphine sulphate, actions that were blocked in other groups when pretreated i.v. with 0.32 μmol of phentolamine, yohimbine, prazosin, or guanethidine. A greater and persistent pressor response occurred following morphine infusion to groups of rats previously injected over 6 days with morphine sulphate, which was associated with tachycardia during the later stages of the 15-min morphine sulphate infusion period. The prolonged pressor and tachycardic responses of this 6-day chronically injected group were completely blocked in another group pretreated i.v. with both phentolamine and propranolol (0.32 μmol). The results suggest that morphine sulphate infusion to conscious, drug-naive rats evokes classical hypotensive effects due to decreases in mean heart rate caused by activation of parasympathetic vagal activity. With 3 or 6 days of chronic morphine sulphate administration beforehand, subsequent i.v. infusion of morphine sulphate evoked pressor actions felt to be caused by a progressive activation of the sympathetic nervous system. These events cause vasoconstriction of peripheral vasculature and, with time, increased cardiac frequency, actions that can be blocked by pretreatment with specific α- and β-adrenergic receptor blockers.Key words: drug-naive rats, morphine-pretreated rats, acute hypotension, bradycardia, chronic pressor responses, opiate and non-opiate receptor blockade.

High-speed photography was used to compare the pigeon's response to unsignalled shock with the pigeon's key-peck response. During shock, pigeons flex their neck (i.e., the distance between their eyes and shoulders decreases). Following shock, the neck is extended. During key pecking, the neck remains extended and the head moves toward the key in a slight arc as though attached to a fixed fulcrum. Response topography during pecking and shock appear to be incompatible, and it is concluded that the difficulty in key-peck training pigeons to escape electric shock is due to interference from the unconditioned flexion response. This conclusion supports the species-specific defense theory of escape and avoidance behavior.

Two laboratory experiments are reported which describe the effects of the presence of a neutral in a communication network during the resolution of differences of opinion between two persons. The presence of a neutral was found to be associated with increased resistance to persuasion, increased number of messages between parties, and increased perception of difficulty in resolving the conflict. It was proposed that the neutral sustains conflict by prematurely rendering public the positions of the parties involved. Member tenure and power were found to be positively associated, suggesting that open groups in contrast to closed groups more readily incur conflict.

Hemodynamic responses (blood pressure, as well as cardiac output (CO), peripheral and CNS blood flow changes measured via radioactive microspheres) were analyzed in anesthetized rats 2 min following intrathecal (IT) administration (10 microliters) of either 5-ion control solution or 20 nmol of dynorphin A(1-13) into the lower thoracic space (T10-T12). Mean arterial pressure (MAP) significantly increased within 2 min following IT dynorphin A(1-13) due to rise in total peripheral resistance, whereas CO significantly declined. Two minutes post-IT-dynorphin A(1-13) administration spinal cord blood flow also significantly decreased for 2 cm anterior and 1 cm posterior from the tip of the spinal catheter, which reflected a significant elevation in tissue flow resistance of spinal cord vessels in spite of the reduction of CO. As well, tissue blood flow resistance was also increased at this time in the kidneys and adrenal glands. The results indicate that within 2 min after intrathecal dynorphin A(1-13) administration an acute increase in blood flow resistance of spinal cord vessels around the tip of the spinal catheter occurs, at a time when the animal is also hypertensive. It is suggested that the associated pressor response may, in part, be caused by dynorphin A evoking localized ischemia.

The photochemistry and photophysics of tris(1,10-phenanthroline)chromium(III) ion, Cr(phen)/sub 3//sup 2 +/, following pulsed-laser excitation at 347 nm, have been studied in deaerated acidic and alkaline aqueous media (pH 3.0-11.1) at room temperature by using conductivity and visible optical detection methods. The lifetimes of the lowest doublet excited state(s) from which is derived the major portion of the photochemistry are little affected by changes in pH as monitored by emission and excited-state absorption nor are the initial intensity levels of these phenomena noticeably altered by pH changes. Alterations in pH do have significant effects on the conductivity signals, which correlate to photoaquation. Conductivity studies for natural pH (ca. pH 7.1) provide evidence for a ground-state intermediate with a pK/sub a/ value around 7. In basic media, an apparent single stage of conductivity occurs, and the values of the observed rate constant and the resulting overall change in conductance are dependent upon the concentration of hydroxide ion. The quantum yield for aquation at the highest pH of 11.1 is determined as 0.08 (+/-20%). By contrast, photochemical reaction in acidic media is found to be very much reduced relative to that occurring in alkaline solutions. A mechanism, incorporating a six-coordinate, monodentate phenathroline intermediate,more » is proposed, and it is used to discuss the occurrence of photoracemization and to compare the behavior of Cr(phen)/sub 3//sup 3 +/, where bpy designates the 2,2'-bipyridine ligand.« less

High-speed photography was used to compare the pigeon's response to unsignalled shock with the pigeon's key-peck response. During shock, pigeons flex their neck (i.e., the distance between their eyes and shoulders decreases). Following shock, the neck is extended. During key pecking, the neck remains extended and the head moves toward the key in a slight arc as though attached to a fixed fulcrum. Response topography during pecking and shock appear to be incompatible, and it is concluded that the difficulty in key-peck training pigeons to escape electric shock is due to interference from the unconditioned flexion response. This conclusion supports the species-specific defense theory of escape and avoidance behavior.