Stimulation Research Articles

Growth and Nutrition of Containerized Singleleaf Pinyon Seedlings in Response to Controlled Release Fertilization

Fertilization with four controlled release nutrient formulations, Sierra 17-6-10, Sierrablen 18-7-10, High N 24-4-8, and Osmocote 18-6-12, was evaluated for its capac ity to facilitate development of containerized singleleaf pinyon (Pinus monophylla Torr.& Frem.) planting stock. A water-soluble fertilizer treatment using Peters 20-10-20 and nonfertilized seedlings provided for comparisons of nutrient amendment effects on growth and nutrition , and each fertilizer formulation was applied using low , medium , and high rates . After 24 months , the high application rate of the Peters formulation produced the largest seedlings overall . Among controlled release treatments , the Sierra formulation applied at the medium rate resulted in the great est shoot dimensions , although the low rate of this fertilizer produced the greatest combined shoot and root dry weight . All treatments resulted in low shoot / root ratios with the exception of the high application rate of Sierra 17-6-10 . Overall , fertilized seedlings exhibited high foliar concentrations of N , P , and K but low concentrations of Ca , Mg , Fe , Mn , Zn , and B relative to nonfertilized seedlings . Foliar S was low in all seedlings relative to documented standards for containerized conifers , while Cu was unaffected by treatment . Among fertilized seedlings , moder ately high N uptake coupled with high P generally resulted in the greatest stimu lation of seedling growth . These results indicate that controlled release fertilization , a method particularly well suited to smaller , less mechanized nurseries , can facilitate the production of containerized singleleaf pinyon with careful selection of nutrient formulation and application rate, but that a production period of 2 years is required to grow planting stock with desired attributes.

PHENOBARBITAL ALTERS LIVER AND KIDNEY FUNCTION IN TOLUENE- AND TRICHLOROETHYLENE-TREATED RATS

Effects of two widely used industrial solvents-toluene and trichloroethyleneon liver and kidney function have been studied in laboratory rats after microsomal induction with phenobarbital. Higher efflux of GOT and GPT suggests that phenobarbital pretreatment stimulates hepatic toxicity of toluene in rats. However, a decline in GPT was recorded in phenobarbital- and trichloroethylenetreated rats. Further, observations on alkaline phosphatase suggest that the metabolic disposition of toluene and trichloroethylene is altered by pretreatment with phenobarbital. Phenobarbital potentiates the necrotizing damage caused by toluene; however, it offers protection against cholestatic injury. In trichloroethylene-treated rats as well, only partial protection could be offered by phenobarbital. Pretreatment of rats with phenobarbital results in a noticeable stim ulation of hepatic cytochrome P450s that are responsible for the metabolism of various drugs and xenobiotics. However, responses are typified by the multiple f...

Acute mesenteric ischemia after open heart surgery.

Acute mesenteric ischemia is a rare but severe complication after open heart surgery. Its incidence (0.2-0.4%) is quite low, but mortality rates are ranging between 70% and 100%. From October 1992 to December 1996, 4,640 patients underwent open heart surgery with cardiopulmonary bypass: 74.6% coronary artery bypass graft (CABG) operations, 23.2% valve replacement including aortic repairs, and 2.2% corrections of congenital heart diseases or tumors of the heart. The overall mortality rate (30 days) was 3.4%, and after CABG, 2.9%. Twelve patients (0.26%), following CABG (one combined with aortic valve replacement, one with mitral reconstruction, and one with carotid disobliteration) developed signs of acute mesenteric ischemia in the early postoperative period (day 1 to 5). In all patients various abdominal symptoms, leukocytosis, acidosis, hyperlactatemia, hyperosmolality, renal failure, and, finally, hemodynamic instability were observed. Eleven patients underwent emergency laparotomy. Mesenteric angiography was done if possible in still stable patients (n=7); it showed severe stenosis or occlusion prior to the operation in each case. Other diagnostic methods were not reliable. In six patients (55%) during the first look, extensive bowel necrosis was found and in five patients an ischemic intestine but no necrosis was detected. Of these, three patients were affected by extensive bowel gangrene at the second look. In the fourth patient a disseminated peripheral ischemia of the entire small intestine was found intraoperatively. After mechanical release and stimulation normal bowel function could be reestablished. One patient underwent percutaneous transluminal angioplasty prior to the laparotomy. Bowel perfusion was still deteriorated but no necrosis was found intraoperatively. These patients were the only survivors in the investigated group; 10 of 12 patients (83.3%) died in the early postoperative period (day 1 to day 6). Predisposing factors for mesenteric ischemia are: arteriosclerotic patients after CABG (100%), age >70 years (91.7%), hyperosmotic dehydration (100%), and cardiac ischemia in 25%. Mesenteric ischemia is a fatal complication with high mortality rates after open heart surgery, especially in older, dehydrated patients with generalized atherosclerotic vessel disease. As the acute mesenteric ischemia usually starts during anesthesia or in the early postoperative period, setting of immediate diagnosis is very difficult. With the occurrence of typical symptoms diagnostic and therapeutic procedures (angiography and laparotomy) must be done very urgently owing to the life-threatening mesenteric process. When mesenteric gangrene already has taken place, the prognosis is very poor, despite extensive resection. Prevention can be exercised by avoiding perioperative hyperosmotic dehydration of patients at high risk.

Efficacy of a Hybrid Upper Limb Neuromuscular Electrical Stimulation System in Lessening Selected Impairments and Dysfunctions Consequent to Cerebral Damage

Objective: The purpose of this study was to test the efficacy of a new computerized neu romuscular electric stimulation system (Handmaster™) in improving selected im pairments and functional measures of patients who survived stroke and traumatic brain injury (TBI).Methods: Survivors of stroke (n = 13) and TBI (n = 7) with chronic paralysis lasting 6.8 ± 7.8 years (range 1 to 29 years) participated in a home program of elec trical stimulation. The device is a hybrid of a hand-forearm splint that incorporates five surface electrodes and a computerized electrical stimulator. The patterned stimu lation elicits finger flexion and extension, lateral pinch, and grasp of the paralyzed hand. Patients practiced daily for 3.4 ± 0.5 hours over a mean duration of 13.1 ± 6.6 weeks. Assessment included goniometric measurements of wrist and elbow rest ing posture, passive and active joints motion, linear distance of fingers to palm, Ash worth scale, and the ability to hold a 1 kg load in the affected hand. The Frenchay a...

Human resource issues in cytotoxic drug dispensing

Introduction. The human resource issues for phar macists manipulating and dispensing cytotoxic drugs in safety cabinets and clean rooms, in accordance with Australian Standards, have been investigated. The technology is regulating, resulting in very formal procedures and work practices. Often staff work under conditions of restricted environmental stimula tion that can have effects on cognitive functioning and reduce efficiency for demanding tasks. Methods. Discussions were held with senior staff of twenty hospitals treating patients with cancer, one manufacturing facility, and one research laboratory, regarding work in cytotoxic drug suites. A survey was administered to staff working in these facilities. Issues explored included: work practices; rosters; cleaning; work flow; ergonomics; quality of work environment; clothing; certification of facilities, and training. Results and Discussion. The survey shows that the major stressors for people working in the facilities are the physical conditions, especially the tempera ture, and the lack of control over workflow. It confirms the importance of windows in the working environment and the need for communication facili ties. Design deficiencies in the technology that impact the quality of the work environment are identified. There are age differences with regard to perceptions of risk from cytotoxic drugs. The study identifies the need for further training, both in technique and understanding of the technology. Conclusion. Whilst minimising risk to staff, the adoption of the technology has had an impact on environment. Identification of these issues should enable improved facilities and work environment.

Oxygen uptake during arm cranking with and without leg electrical stimulation in able bodied individuals

Ten able bodied subjects (AB) volunteered to be tested with a Respond II neuromuscular stimulator applied to the lower extremities during submaximal arm crank exercise (ACE) to determine its effect on heart rate (min−1) and VO2 in ml·min−1 ·kg−1. One to two hours after a maximal ACE test, subjects performed four 9‐minute submaximal bouts of ACE; two at 25% and two at 70% of VO2peak. Each work rate was performed with and without, a randomly ordered, electrical stimulation (ES) of the quadriceps and hamstring muscle groups respectively. Electrical stimulation intensity was determined by a subject's maximal tolerance. Data, from four submaximum tests were analyzed with a two 2×2 repeated measures analysis of variance. The main effects were work rate (25% VO2peak and 70% VO2peak) and electrical stimulation (STIM) no stimulation (NOSTIM). No statistical differences was found between the STIM and NOSTIM in VO2 or heart rate at either 25% VO2peak (11.0 ml·min−1·kg−1 vs. 11.2 ml·min−1·kg−1; and 89 min−1 vs. 88 min−1 respectively) or 70% VO2peak (22.8 ml·min−1·kg−1 vs. 22.8 ml·min−1·kg−1; 128 min−1 vs. 127 min−1 respectively). There was a difference in VO2 and heart rate for the main effect of work rate 25%VO2peak or 70%VO2peak (11.1 ml·min−1 ·kg−1 vs. 22.8 ml‐min−1 ·kg−1; 88 min−1 vs. 127 min−1). The results of this study may have been affected by the low level of ES intensity used, due to human subjects' ES guidelines, and use of the lower limbs for stability with increasing intensity of work rate.

EVALUATION OF 17,20-DESMOLASE (DES) ACTIVITY OF P450c17, 3β-HYDROXYSTEROID DEHYDROGENASE (3βHSD) AND 17β-HSD ACTIVITIES IN PRIMARY CULTURE OF HUMAN IMMATURE TESTICULAR CELLS

In humans. Leydig cells are present during the first 6 months of postnatal life and they regress thereafter. We have described that basal (B) secretion of testosterone (T) in human testicular cells in culture is higher between 1 and 7 months (M) of age than between 8 and 36 M. Furthermore. T was stimulated by LH, FSH and GH only in the younger group (Ped Res 1995, in press). In the present study of primary cultures of human testicular cells obtained at necropsy, we have evaluated the activity of 3 enzymes of testicular steroidogenesis, 17,20 -DES, 3βHSD and 17β HSD, by correlating the production of T (the final product of steroidogenesis) with that of 17OH-progesterone (17OHP) (for 17,20-DES and 17βHSD), dehydroepiandrosterone (DHEA) (for 3βHSD and 17βHSD) and androstenedione (A) (for 17βHSD). Activities were estimated from the slopes (SL) of regression lines. Levels of T, 17OHP, DHEA and A were determined by RIA in conditioned media of day 6 of culture. The following groups (G) were defined, G1B, aged 1 to 7 months (n=8), G1 ST same age but under chronic stimulation (ST) with LH (10 ng/ml), FSH (2 ng/ml) or GH (50 ng/ml) and G2B, aged 8 to 36 M (n=7). Between 17OHP and T, SL was 1.95(r=0.73, p=0.0001) in G1B and 6.99 (r=0.97, p=0.0001) in G2B These two SL were significatively different (p<0.0005) but no difference was observed between G1B and G1ST. Between DHEA and T, SL was 0.60 (r=0.967 p<0.0001) in G2B but no significant correlation was observed in G1B nor in G1ST. Between A and T, SL were similar, 0.48 (r=0.78, p=0.0001) and 1.09 (r=0.56, p=0.02) in G1B and G1ST, respectively, but different (p<0.005) from G2B, 2.18 (r=0.99, p=0.0001). Furthermore, in G1B and in G2B SL between A and T were significantly lower than between 17OHP and T (p<0.005 in both). It is concluded that in immature human testicular cells, the activities of 17,20 DES, 3βHSD and 17βHSD do not change after trophic stimulation. The absence of significant correlation between DHEA and T suggests that 3βHSD is very active. Since SL are higher in G2B in the pre-Leydig cells of the regressed testis. the 3 enzymes analysed are probably low. Finally, the fact that SL between A and T is smaller than between 17OHP and T suggests that 17,20-DES is a limiting enzyme activity in the steroidogenesis of the immature human testis.

Liver sinusoidal lymphocytes: their immune functions

Abstract Recent studies strongly suggest that the liver plays an im portant immunoregulatory role. Ev idence of its role in general immune responsiveness originates from ob servation that, in recipients of liver grafts, the survival of other allo-grafts is significantly prolonged. The question arises as to which blood lymphocyte subsets, most likely to be responsible for this phenomenon, marginate in liver sinusoids. To study this problem, a liver ex vivo perfusion model was designed for rats. In situ W/WAG livers were wa shed clear of sinusoidal marginating cells prior to and after 1 h perfusion with syngeneic blood. The number of blood cells retained in liver sinu soids, their phenotypes, the respon siveness to mitogen (PHA, 90 μg/ ml) and cytotoxicity against YAC-1 tumour cells were examined. Our studies showed that rat liver retains in the sinusoids a population of blood cells, enriched in NK, CD8′ and MHC class II+ cells, displaying a high cytotoxic activity and low re sponsiveness to mitogen stimula tion, with a capacity of about 106 cells/g of tissue.

A Possible Involvement of Monoaminergic and Opioidergic Systems in the Analgesia Induced by Electro-Acupuncture in Rabbits

To elucidate mechanisms involved in analgesia induced by effects of electro-acupuncture (EAP), effects of EAP on evoked potentials and release of substance P (SP) following tooth pulp stimulation (ST) in the superficial layers of the trigeminal nucleus caudalis (Vc-I-II) were studied in the rabbit. The potentials evoked by ST were composed of two main components with conduction velocity of ca. 30 m/sec (fast component) and ca. 12 m/sec (late component). The late component was significantly inhibited by morphine (10 mg/kg, i.v.) or CP-96,345 (5 mg/kg, i.v.), an SP antagonist. This inhibitory effect of morphine was antagonized by naloxone (1 mg/kg, i.v.) or methysergide (5 mg/kg, i.v.). In addition, the late component was significantly inhibited by EAP, which was observed in ca. 70% of the rabbits examined. This EAP-induced inhibitory effect was antagonized by naloxone (1 mg/kg, i.v.) or methysergide (5 mg/kg, i.v.), but not by prazosin (5 mg/kg, i.v.) and yohimbine (1 mg/kg, i.v.). The stimulus-evoked SP release was inhibited by EAP, which was significantly antagonized by pretreatment with naloxone (1 mg/kg, i.v.) or methysergide (5 mg/kg, i.v.). These results suggest that one of the mechanisms of analgesia induced by EAP is due to inhibition of the stimulus-evoked SP release in the Vc-I-II through activation of the descending serotonergic systems linking up with opioidergic systems.

Hypothalamic modulation of the arterial chemoreceptor reflex in the anaesthetized cat: role of the nucleus tractus solitarii.

1. There is evidence in the literature of a mutual facilitatory interaction between the arterial chemoreceptor reflex and the alerting stage of the defence reaction, particularly in relation to the patterning of cardiorespiratory activity. The present study has been designed to test the hypothesis that a portion of this interaction involves synaptic interactions within the nucleus tractus solitarii (NTS). 2. The study has involved an analysis of the effective interactions between the stimulation of the arterial chemoreceptors and the hypothalamic defence area (HDA) on the activity of NTS neurones recorded in anaesthetized, paralysed and artificially ventilated cats. 3. A group of eighteen NTS neurones was classified as chemosensitive, on the basis of displaying EPSPs on sinus nerve stimulation (SN) and their failure to show an excitatory response to baroreceptor stimulation. Thirteen of these neurones displayed pronounced excitatory responses to chemoreceptor stimulation. In sixteen of these neurones HDA stimulation elicited an EPSP; in four of these sixteen neurones this early EPSP was followed by an IPSP. In the remaining two (of 18) neurones HDA stimulation provoked no obvious synaptic response but facilitated the efficacy of both chemoreceptor inputs and SN stimulation. 4. Neurones shown to receive convergent inputs from the arterial chemoreceptors (and SN stimulation) and HDA, often displayed excitatory responses to stimulation of other peripheral inputs. Vagally evoked EPSPs were observed in nine neurones, SLN-evoked responses in seven neurones and aortic nerve-evoked EPSPs in three neurones. 5. The organization of these synaptic interactions is discussed and these data are used to explain the pattern of interaction between chemoreceptor, baroreceptor and HDA inputs within the NTS. Conclusions are drawn regarding the functional role of different classes of NTS neurone, based on the findings in this and the accompanying two papers.

Does hypothalamic neuronal activity modulate by the auricular stimulation on experimental obese rats?

It has been known that an auriculotherapy occasionally affected dramatic body weight reduction for obese patients, although its physiological and anorexigenic functions are not clear. Effects of auricular st imulation on feeding related lateral (LHA) and ventromedial (VMH) hypothalamic neuronal activity in the normal and experimental ( hypothalamic and dietary ) obese rats were investigated. The LHA and/or VMH neuronal activity were recorded from feeding related region , on the Wistar SPF/VAF male and experimental (hypothalamic and dietary) obese rats, anesthetized with urethane-chloralose, under stereotaxic co-ordination. Recording was through 3M-KCI micro-glass electrode, while stimulating the ipsilateral vagal innervated region of the auricle. This is equivalent to the cavum conchae in human, and was identified by resistance less than 10-50 kilo-ohm. The stimulating electrode was a stainless-steel ear acupuncture (0.12 x 2.0 mm). Results showed that the latency of potentials evoked in the LHA by unilateral stimulation of a specific site in the ear, was 28.1+/-3.3 ms (8-92, n=41). LHA neuronal activity was suppressed ( 45.6%, n=12, p<0.01), and VMH activity was excited ( 60.5%, n=18, p<0.01). The auricular acupuncture stimulation can clearly modulated feeding related hypothalamic neuronal activity of experimental, both hypothalamic and dietary, obese rats. These auricle acupuncture stimulation effects were correlated to the degree of obesity. In conclusion, the results suggest that auricular acupuncture stimulation may not reduced appetite reducing, but is more likely to be concerned with satiation formation and preservation. Thus, auricular acupuncture should be more effective onobese rats than on normal rats.

The Effect of Continuous Infusion of Dobutamine on the Maximal Forearm Skin Blood Flow and Plasma Neuropeptide Y Level in Patients with Congestive Heart Failure

To investigate whether continuous infusion of therapeutic doses of dobu tamine will influence the plasma neuropeptide Y (NPY) and the vasodilator capacity of nonacral skin in congestive heart failure (CHF) patients, the authors measured plasma NPY, norepinephrine (NE), and epinephrine (Epi) in 21 CHF patients, New York Heart Association (NYHA) function class III-IV, before and after four consecutive days' treatment by continuous infusion of dobutamine. Nine of these patients underwent laser Doppler flowmetry with a modified heat ing probe to measure the forearm skin blood flow for seventy minutes. They were measured at rest from room temperature to locally heated temperature of 42°C, a maneuver known to selectively and maximally vasodilate skin. Another 9 age-matched CHF patients, NYHA function class II, not requiring dobu tamine treatment, were treated with placebo to follow the same protocol. Mean arterial blood pressure and heart rate did not change significantly before and during treatment in both groups. The maximal forearm skin blood flow changed significantly from the control after dobutamine treatment in all the following four days (12.3 ± 2.4 versus 21.8 ± 4.4, 21.2±2.9, 22.3 ± 4.9, 23.0 ± 5.1 Volt, p &lt; 0.05), but this was not observed in the placebo group (11. 8 ± 2 . 9 versus 13 .3 ± 2.4, 11.6 ± 1.8, 14.6 ± 2 .5, 10. 0 ± 1.5, p = NS) . The NPY, NE, and Epi did not show any alteration before and during four days' treat ments with dobutamine in 9 patients. Plasma NPY, NE, and Epi of 21 patients before dobutamine treatment were all elevated when compared with 115 age- matched control subjects (40 ± 3.0 versus 23.2 ± 0.9 pmole/L, p &lt; 0.0005 for NPY; 3.7 ± 0.1 versus 2.4 ± 0.1 pmole/mL, p &lt; 0.0005 for NE: and 1.9 ± 0.1 ver sus 1.6 ± 0.1 pmole/mL, p &lt; 0.03 for Epi). Plasma NPY correlated better with NE than with Epi after dobutamine treatment. Hence the authors conclude: (1) the increment of skin blood flow by dobu tamine may be due to increased cardiac output or direct vasodilator effect. (2) NPY, NE, and Epi elevated in CHF, but they were not affected by acute stimula tion of sympathetic activity by dobutamine treatment. (3) The better correlation between NPY and NE indicates its origin from sympathetic nerve terminals, and NPY may play a role in the pathophysiology of CHF.

Influence of electro-acupuncture on the release of substance P and the potential evoked by tooth pulp stimulation in the trigeminal nucleus caudalis of the rabbit

The effects of electro-acupuncture (EAP) on the release of substance P (SP) and the responses evoked by tooth pulp stimulation (ST) in superficial layers of the trigeminal nucleus caudalis (Vc-I,II) were studied in rabbits. ST evoked increase in release of immunoreactive SP (iSP). This increase was inhibited by EAP in 9 of 13 animals. The potentials evoked by ST were composed of two main components with latency times of ca 4.3 msec and ca. 9.4 msec. The latter component, reflecting the excitation of Aδ fibers, was significantly inhibited by CP-96,345 (3 mg/kg, i.v.), an SP antagonist. EAP also inhibited the latter component in 8 of 11 animals. These results suggest that one of the mechanisms of analgesia induced by EAP is inhibition of stimulus-evoked SP release in the Vc-I,II.

Indices of Sympathetic Vascular Innervation in Scleroderma Patients Treated by Epidural Spinal Cord Electrical Stimulation (ESES)

In an attempt to explain the epidural spinal cord electrical stimulation (ESES) mechanism of action on microcirculation, the authors measured arterial and venous plasma concentration of norepinephrine (NE), by chromatography, in 17 patients (16 women - 1 man, mean age forty-seven years, range: twenty- four to sixty-four years) affected by scleroderma (15 patients) and Raynaud's disease (2 patients), treated by ESES (mean follow-up 29.3 months, range: one to forty-nine months). Blood was sampled with the patient in the supine position, resting at least for thirty minutes, in environmental standard conditions, from a brachial vein (without tourniquet) and a radial artery, with pacemaker off for twelve hours and pacemaker on for thirty minutes. Microcirculatory modifications induced by ESES were also evaluated in all patients by transcutaneous oxygen tension (TcPO2) and laser Doppler flow (LDF), simultaneously measured with the pa tient in the supine position, on the palm (thenar and hypothenar eminences) during three thirty-minute consecutive phases at 42 ° C and 45°C (phase I: pace maker off for twelve hours; phase II: pacemaker on; phase III: pacemaker off). For technical reasons, NE dosages were available in only 12 patients. Cate gorizing the patients on the basis of clinical results (group A, excellent-good, 9 patients; group B, poor-null, 3 patients) the authors noted after the ESES stim ulation: 1. The vasodilatation index (TcPO2 42°C/TcPO2 45 ° C) increased in phase II and phase III (phase I vs phase II, p &lt; 0.001; phase I vs phase III, p &lt; 0.01). 2. The LDF flow differences between 42°C and 45°C were statistically sig nificant in responders between phase I and phase III (p &lt; 0.01). 3. The physiologic norepinephrine arteriovenous ratio was inverted in 7 of 9 patients of group A and in none of group B (p &lt; 0.05). TcPO2 and LDF are useful noninvasive techniques to evaluate microcircula tory modifications induced by ESES. Moreover, the arteriovenous ratio de crease in plasma norepinephrine may explain the ESES effect on microcircula tion and the reduced vasomotor tone.

Metabolic and contractile responses of rat fast-twitch muscle to 10-Hz stimulation

Contractile and metabolic responses of rat fast-twitch gastrocnemius-plantaris muscles were studied. Acute in situ 10-Hz stimulation (STIM) for two 60-min periods, separated by 60 min of recovery (REC), was used. Muscles were removed at 1, 3, 15, 60, 75, 120, 123, or 180 min for metabolite measurements. Twitch and tetanic tensions were reduced to 36 and 28% of initial during the first 60 min of STIM. During REC, these tensions returned only to 56-58% of initial by 120 min. These contractile responses did not parallel changes in metabolites in mixed muscle. pH was reduced from 7.0 to 6.4 by 1 min, but by 15 min of STIM had returned to resting levels. Free ADP and AMP increased 3- and 15-fold during STIM, then decreased to resting levels by 3 min of REC. The most sensitive indicator of metabolic stress during STIM and REC was the phosphorylation potential, which varied up to 40-fold. After initial phases of depletion, ATP and phosphocreatine levels were partially restored despite ongoing STIM. Approximately 75% of the change in ATP level could be accounted for by IMP. In red gastrocnemius [fast-twitch red (FTR)] muscle, IMP was increased by 3 min of STIM but returned to control values by 60 min. Thus reamination of IMP occurred during contractions of FTR muscle. Metabolic and contractile responses during the second STIM period (120-180 min) were similar to the first. This cycle of metabolic and contractile responses occurs in fast-twitch muscle which, with chronically repeated STIM and REC periods, undergoes large phenotypic changes as a result of use.

Glycogen Phosphorylase in the Fat Body of Two Cockroach Species, Periplaneta americana and Nauphoeta cinerea: Isolation, Partial Characterization of Three Forms and Activation by Hypertrehalosaemic Hormones

The presence of endogenous phosphorylase kinase and phosphorylase phosphatase in crude extracts of fat bodies from the cockroaches Nauphoeta cinerea and Periplaneta americana is demonstrated in vitro by activation/inactivation of glycogen phosphorylase under appropriate conditions. Fractionation of fat body extracts of both cockroach species on an anion-exchange medium results in the elution of three peaks with phosphorylase activity. According to their AMP dependency these activity peaks are designated as phosphorylase b (inactive without AMP), phosphorylase ab (active without AMP, but several times stimulated with AMP) and phosphorylase a (active without AMP). It is shown chromatographically that incubating crude extracts of fat bodies from both cockroaches, under conditions where the phosphorylase kinase is active, results in all phosphorylase b being converted to the ab- or a-form, whereas under conditions where the phosphorylase phosphatase is active all phophorylase a is converted to the ab- or b-form. Endogenous phosphorylase kinase of N. cinerea crude fat body extract can convert vertebrate phosphorylase b into the a-form, and, conversely, vertebrate muscle phosphorylase kinase and phosphorylase phosphatase, respectively, are able to convert partially purified N. cinerea phosphorylase ab or b and the ab- und a-form, respectively. In resting cockroaches most of the phosphorylase activity residues in the b-form and only a small fraction (10%) in the a-form, whereas between 26% (N. cinerea) and 35% (P. americana) occurs in the ab-form. Injection of endogenous hypertrehalosaemic peptides into N. cinerae (the decapeptide Bld-HrTH) or P. americana (the two octapeptides Pea-CAH-I and II) causes interconversion of phosphorylase; after injection, mainly (60%) phosphorylase a is present, while 25% and 15% exists in the ab- und b-form, respectively. Purification of the three phosphorylase forms from N. cinerea is achieved by anion-exchange chromatography on DEAE-Sephacel followed by affinity chromatography on AMP-Sepharose. The final specific activities are 2.1, 6.9 and 27.2 U/mg protein for the a-, ab- und b-form. The molecular mass of the active molecules on gel filtration is between 173,000 and 177,000, and SDS gel electrophoresis reveals a subunit mass of 87,100, suggesting a homodimeric structure for all three forms. Kinetic studies show hyperbolic saturation curves for the substrates glycogen and Pi, respectively, with KM-values of 0.021, 0.019 and 0.073% for glycogen and 8.3, 6.3 and 17.9 mM for Pi (a-, ab- and b-form). Phosphorylase a exhibits a more or less hyperbolic response to AMP and needs 70 microM AMP for maximal stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Induction of ethylene biosynthesis is correlated with but not required for induction of alkaloid accumulation in elicitor-treated Eschscholtzia cells

Cell suspension cultures of Eschscholtzia californica produce almost no ethylene under normal growth conditions. Addition of 1-aminocyclopropane carboxylic acid (ACC) to the culture results in a strong stimu lation of ethylene formation, indicating that the ethylene-forming enzyme is constitutively present in the cells. Incubation of the cells with different amounts of an elicitor derived from yeast extract leads to a dose-dependent induction of ACC synthase and ethylene biosynthesis. This effect is correlated with the previously described induction of benzophenanthridine alkaloids. Aminoethoxyvinylglycine, a known inhibitor of ACC synthase, suppresses the induction of ethylene biosynthesis but does not affect induction of alkaloid accumulation, indicating that biosynthesis of ACC and ethylene are not required for induction of alkaloid accumulation.

Influence of handling systems on meat quality of beef and some remarks concerning slaughter handling of reindeer

The combined effects of corral design and corral time on the incidence of D F D (dark, f i rm, dry meat) in young bulls and calves ( C . W . 100-110 kg) has been studied in two projects compris ing about 1800 young bulls and 600 calves. Three different types of corral design were tested individual pens, large free-range pens (6-10 animals per pen), and tethering. F o r each corral type, various holding periods were studied. The use of a so-called delivery-pen at the producer ' s was also evaluated. The delivery-pen is used for the holding of animals destined for slaughter w h i c h are gathered the day before del ivery in order to assist the transporter and to make loading a one-man job. In the calf project a l o w ceiling in the corral to prevent mount ing was tested. The ultimate p H ( p H u ) was measured in several muscles. Muscles w i t h 5.80 = p H u 6.20 as D F D . The main result can be summarized: In Sweden D F D is the most c o m m o n meat quality deficiency in beef and veal. The shelf life and the frying characteristics w i l l be reduced. The use of individual pens vis-a-vis large freerange pens resulted in a considerably reduced incidence of D F D meat. L o n g holding periods (i.e. overnight) versus short periods in individual pens caused a minor increase in D F D incidence. A corresponding comparison for large pens resulted i n a very substantial increase. W h e n young bulls that had been tethered at the producer ' s were kept tethered overnight in the corral p r io r to slaughter, hardly any D F D meat was found. The use of a delivery-pen caused a dramatic increase in D F D incidence. N o more than 4-5 calves should be housed in a pen, especially if they have to be fenced overnight. The ultimate p H was clearly reduced by lowering the ceiling in the calf-corral to prevent mount ing . The results have been used in the Swedish slaughter industry since 1985. The D F D incidence has been reduced to a m i n i m u m . Based on our results and results f rom F i n n i s h studies on reindeer it is possible to give some theoretical and concluding remarks concerning slaughter handling of reindeer. It w o u l d be recommendable to: shorten the slaughter handling procedure as much as possible. Especially the handling moments of individual animals. move the abattoir to the reindeer instead of mov ing the animals to the slaughter house. slaughter the reindeer during the autumn season. The D F D incidence increases dramatically dur ing the winter season when the animals often w i l l be in a negative energy balance. introduce electrical st imulation of the carcasses to avoid the prob lem of co ld shortening. F i n a l l y , to present detailed recommendations h o w to handle reindeer at slaughter ensuring (i) opt imal meat quality and (ii) proper animal welfare it is necessary to study the various moments i n the slaughter chain and during different slaughter seasons. 16 Rangif er, Special Issue No . 5, 1990

Involvement of descending monoaminergic systems in the transmission of dental pain in the trigeminal nucleus caudalis of the rabbit

Perfusates were taken from the superficial layers of the subnucleus caudalis of the trigeminal sensory nuclear complex (SpVc), the first relay station of dental pain, with a push-pull cannula system and were assayed for endogenous serotonin (5-HT) and catecholamines by high-pressure liquid chromatography with an electrochemical detection. Spontaneous release of 5-HT and epinephrine was observed, while that of norepinephrine was not. Tooth pulp stimulation (ST) tended to increase the level of 5-HT in the perfusates. Pretreatment with morphine at a dose of 10 mg/kg (i.v.) significantly enhanced the release of 5-HT. However, there was no significant difference in morphine effect on the 5-HT level between stimulated and non-stimulated animals. Systemic administration of morphine (10 mg/kg i.v.) completely inhibited the release of immunoreactive substance P from the superficial layers of SpVc evoked by ST, and this inhibition was antagonized by local application of methysergide (10 −4 M). These results suggest that in the superficial layers of SpVc, morphine may primarily activate the descending 5-HT pathway which serves to modulate dental pain transmission.

Properties of cutaneous afferents in diabetic neuropathy.

The technique of percutaneous microneurography was used to study the response properties of 68 cutaneous afferents in 8 diabetic patients and, for comparison, of 104 afferents in 12 normal control subjects. The diabetic patients were neurologically asymptomatic or had a mild sensory neuropathy. Three afferent categories were studied in the diabetic subjects (rapidly adapting type RA and slowly adapting SAI and SAII) in response to mechanical skin stimulation and abnormal responsiveness was encountered in all categories. Distinct abnormalities were seen in about 30% of the RA and in 20% of the SAI type nerve fibres. The abnormalities consisted of the generation of only single action potentials to above threshold stimuli (RA), and of high fatiguability to repetitive stimulation (SAI). A more subtle abnormality was additionally encountered in the slowly adapting SAI and SAII groups. This consisted of low discharge rates to sustained skin indentation, with values statistically significantly different from normal. Absolute mechanical response thresholds and receptive field configurations were similar between diabetic and normal units. The conduction velocities of individual nerve fibres were measured in response to intradermal electrical stimulation. They were similar to normal, regardless of whether the afferents displayed normal or abnormal responsiveness to physiological stimulation of the receptive fields. The data indicate that different cutaneous afferent categories are affected by the disease, and are limited in their ability to transmit trains of action potentials. As a consequence, physiological stimuli may be abnormally encoded in diabetic units. Two hypotheses, one morphological and one biophysical, are proposed for explaining the present findings. The results altogether provide a physiological basis for understanding nerve fibre dysfunction and sensory disturbances in human diabetic neuropathy.