Sunao Tamai

Interleukin-6 stimulates the secretion of adrenocorticotropic hormone in conscious, freely-moving rats.

In order to assess the effect of interleukin-6 on the hypothalamo-pituitary-adrenal axis, we administered recombinant human interleukin-6 to conscious, freely-moving rats. The intravenous injection of interleukin-6 significantly increased the plasma level of adrenocorticotropic hormone 30 min after the injection in a dose-related manner. Immunoneutralization of corticotropin-releasing hormone blocked the stimulatory effects of interleukin-6 on adrenocorticotropic hormone secretion. These observations suggest that interleukin-6 stimulates the secretion of adrenocorticotropic hormone through the corticotropin-releasing hormone and is possibly involved in the interaction between the neuroendocrine and immune system.

Responses of Plasma Adrenocorticotropic Hormone, Cortisol, and Cytokines during and after Upper Abdominal Surgery

There is currently accumulating evidence for bidirectional communication between the neuroendocrine and immune systems. Various cytokines have been suggested to be involved in the stimulation of stress hormone secretion during the times of infection and inflammation. To assess the possible involvement and pathophysiologic significance of cytokines in the mechanisms responsible for the perioperative stress response of the hypothalamo-pituitary-adrenal axis, we observed the changes of plasma adrenocorticotropic hormone and cortisol levels together with those of plasma endotoxin and cytokine levels. In patients undergoing pancreatoduodenectomy, perioperative stimulation of adrenocorticotropic hormone and cortisol secretion was accompanied by a significant elevation of plasma cytokine levels. Application of epidural block up to the upper thoracic levels failed to suppress this stress response effectively. In patients undergoing unilateral total hip replacement, the response of plasma hormone levels was smaller and briefer with no significant increase of plasma cytokine levels. Application of epidural block up to the lower thoracic levels suppressed this hormonal response almost completely. In patients undergoing pancreatoduodenectomy, a significant elevation of plasma endotoxin level was followed by a gradual but significant elevation of plasma tumor necrosis factor alpha and interleukin-6 levels. It seems likely that the stimulatory effects of these cytokines on the secretion of adrenocorticotropic hormone and cortisol might be involved in the development of the greater and more prolonged stress response of hypothalamo-pituitary-adrenal axis. Our present study suggests that not only neural input from the surgical wound but also stimulation of cytokine production were responsible for the development of the stress response of the hypothalamo-pituitary-adrenal axis during and after upper abdominal surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic hormone-releasing activities of interleukins in a homologous invivo system

We compared adrenocorticotropin-releasing activities of several interleukins in a homologous or heterologous in vivo system. Intravenous injection of rat interleukin-1 alpha significantly increased plasma adrenocorticotropin in conscious, freely-moving rats 30 min after the injection, and the effect was 10 times greater than that of human interleukin-1 alpha. Rat interleukin-2 affected plasma adrenocorticotropin in a much slower manner and increased its levels significantly 120 min after the injection. Human interleukin-2 had no effect on plasma adrenocorticotropin. Thus, species difference in the experimental system should be considered to assess the physiological significance of cytokines in the neuroendocrine system.

Chronic effects of interleukin-1 on hypothalamus, pituitary and adrenal glands in rat.

To assess the chronic effects of interleukin-1 (IL-1) and IL-2 on the hypothalamo-pituitary-adrenal axis in vivo, we administered recombinant human (rh) IL-1 alpha, rhIL-1 beta or rhIL-2 (2.0 micrograms/day) repetitively to adult male rats for 10 days. In rhIL-1 beta-treated rats, adrenocorticotropic hormone-like immunoreactivity (ACTH-LI) of the anterior pituitary appeared to increase first on day 3 followed by an increase of corticotropin-releasing hormone (CRH)-LI both in the hypothalamus and in the adrenal gland after day 7. At the end of the 10-day treatment, wet weights of the adrenal glands of rhIL-1 beta-treated rats increased significantly compared with those of control rats. Plasma ACTH levels in rhIL-1 beta-treated rats at the sampling time continued to be elevated throughout the experimental period. Under the same experimental design, rhIL-1 alpha increased plasma ACTH levels at the sampling time without changes in adrenal weight or in the peptide contents investigated. The same amount of rhIL-2 had no effect on these measured variables during the 10-day treatment. These data indicate that the repetitive administration of IL-1 beta resulted in chronic effects in the hypothalamo pituitary-adrenal axis to increase the activities in these organs during the treatment and, moreover, IL-1 possibly has a positive direct effect on the CRH-containing cells in the adrenal glands.

Positive end-expiratory pressure ventilation decreases plasma atrial and brain natriuretic peptide levels in humans.

To investigate the possible role of atrial and brain natriuretic peptides (ANP and BNP) in the renal effects of mechanical ventilation with positive end-expiratory pressure (PEEP), we measured changes in plasma ANP and BNP levels during PEEP in patients undergoing subtotal esophagectomy. Application of 15 cm of H2O PEEP for 1 h decreased the levels of plasma ANP and BNP from 24.4 +/- 5.5 (mean +/- SEM) and 19.0 +/- 3.5 fmol/mL to 14.4 +/- 2.1 and 15.3 +/- 3.0 fmol/mL, respectively (P < 0.05). The level of plasma cyclic guanosine monophosphate, an intracellular second messenger of ANP and BNP, also decreased from 8.4 +/- 1.5 to 5.7 +/- 0.8 pmol/mL (P < 0.05). PEEP increased the levels of plasma arginine vasopressin from 2.0 +/- 0.5 to 4.2 +/- 1.2 pg/mL, aldosterone from 36.1 +/- 4.9 to 65.3 +/- 12.7 pg/mL, and plasma renin activity from 1.4 +/- 0.5 to 2.7 +/- 0.7 ng.mL-1.h-1. During PEEP ventilation, urine output, urinary sodium and potassium excretion, osmolar clearance, and cardiac index all decreased. PEEP increased free water clearance, right atrial pressure, pulmonary arterial pressure, and pulmonary capillary wedge pressure. The level of plasma endothelin, mean blood pressure, and heart rate did not change significantly. These results suggest that not only hemodynamics and the vasopressin and renin-angiotensin-aldosterone system, but also the natriuretic peptide system (ANP and BNP), are involved in the renal effects of PEEP.

Interleukin-1β analogues with markedly reduced pyrogenic activity can stimulate secretion of adrenocorticotropic hormone in rats

We examined the adrenocorticotropic hormone-releasing activities of several human interleukin-1 beta analogues that have markedly reduced pyrogenic activities in rats. Among the analogues tested, [Gly4]-, [Leu93]- and [1-148]-interleukin-1 beta increased the plasma adrenocorticotropic hormone level to almost that induced by authentic human interleukin-1 beta. Modifications of the N-terminus of the authentic molecule, i.e., [7-153]- and [Des-Ala1, Asp4]-interleukin-1 beta, significantly reduced the hormone-releasing activity. These data suggest that the adrenocorticotropic hormone-releasing activity of human interleukin-1 beta resides in the N-terminal structure of the authentic peptide and can be separated from its pyrogenic activity.

Comparison of endocrinological stress response associated with transvaginal ultrasound-guided oocyte pick-up under halothane anaesthesia and neuroleptanaesthesia

Twelve patients with mechanical infertility in the in vitrofertilization program were studied. Seven of them received halothane anaesthesia and the other five received neuroleptanaesthesia. Higher plasma prolactin levels and lower plasma progesterone levels were observed in the neuroleptanaesthesia group than in the halothane group during and after transvaginal ultrasound-guided oocyte pick-up. Plasma adrenocorticotropic hormone and cortisol levels of the patients suggested that surgical stress was minimal in both groups. It is likely that droperidol and fentanyl, both used in neuroleptanaesthesia, were responsible for the hyperprolactinaemia which was followed by inhibition of progesterone production. These agents, therefore, are not recommended as anaesthetic agents for transvaginal ultrasound-guided oocyte pick-up.RésuméDans le cadre d’un programme de fertilisation in vitro, on a fait la cueillette d’ovules par voie transvaginale avec échographie chez 12 femmes infertiles. Pour ce faire, nous en avons anesthé siées sept avec de l’halothane et cinq par neuroleptanesthésie. En mesurant les niveaux plasmatiques pendant et après la procédure, nous avons trouvé plus de prolactine et moins de progestérone avec l’halothane qu’avec la neuroleptanesthésie. Les quantités d’ACTH et de cortisol plasmatiques, faibles dans les deux groupes, suggèrent un niveau minimal de stress chirurgical. II est probable que le dropéridol et le fentanyl, utilisés dans le groupe neuroleptanesthésie, soient responsables d’une hyperprolactinémie suivie d’une inhibition de la sécrétion de progestérone et de ce fait, ils devraient être évités lors de la cueillette d’ovules.

Noise Exposure From High-Flow Nasal Cannula Oxygen Therapy: A Bench Study on Noise Reduction

BACKGROUND: High-flow nasal cannula (HFNC) oxygen therapy produces noise at a level such that patients often complain. However, the noise level has not been measured digitally. METHODS: We evaluated 3 types of HFNCs without filters and 2 types with filters attached for noise reduction. Optiflow (with and without a filter), MaxVenturi (with and without a filter) and AIRVO2 (without a filter only) were positioned at the center of a hospital room. We measured the noise levels at the distance of 1 m from the equipment at various total flows (30, 40, 50, 60 L/min) and FIO2 (0.40, 0.60, and 0.90). RESULTS: Noise levels were increased with the AIRVO2 and MaxVenturi when total flow and FIO2 were increased. Noise levels decreased with the MaxVenturi when a filter was used. The noise level did not change with the Optiflow when total flow and FIO2 were increased. The noise level decreased in the groups with AIRVO2 and Optiflow compared with MaxVenturi without a filter. CONCLUSIONS: The findings in this study show that the noise level of HFNC/Venturi could be reduced by attaching an intake filter. However, the noise level of HFNC/blender and HFNC/turbine decreased in comparison with HFNC/Venturi without an intake filter

Possible Role of Cytokines in the Stress Response of the Hypothalamo-Pituitary-Adrenal Axis During Upper Abdominal Surgery

It is well known that surgical invasion activates the hypothalamo-pituitary-adrenal (H-P-A) axis and induces marked elevation in plasma adrenocorticotropic hormone (ACTH) and Cortisol levels during and after surgery. The stress response of plasma ACTH and Cortisol levels cannot be totally suppressed by epidural [1] or subarachnoid anesthesia [2], especially in upper abdominal surgery [3], which suggests the involvement of some factor(s) other than afferent neural output arising from the injury site [4]. Some cytokines have recently been suspected to play important roles in the activation of the H-P-A axis at the times of infectious challenge and other stressful conditions [5–7]. To assess the possible involvement and role of cytokines in the stress response of the H-P-A axis during surgical procedures, we observed changes in the levels of plasma ACTH, Cortisol, endotoxin, tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) in patients undergoing upper abdominal surgery. We then investigated the ACTH-releasing activities of these cytokines using an in vivo experimental system.