Simulating Tsunami Inundation and Soil Response in a Large Centrifuge.

Tsunamis are rare, extreme events and cause significant damage to coastal infrastructure, which is often exacerbated by soil instability surrounding the structures. Simulating tsunamis in a laboratory setting is important to further understand soil instability induced by tsunami inundation processes. Laboratory simulations are difficult because the scale of such processes is very large, hence dynamic similitude cannot be achieved for small-scale models in traditional water-wave-tank facilities. The ability to control the body force in a centrifuge environment considerably reduces the mismatch in dynamic similitude. We review dynamic similitudes under a centrifuge condition for a fluid domain and a soil domain. A novel centrifuge apparatus specifically designed for exploring the physics of a tsunami-like flow on a soil bed is used to perform experiments. The present 1:40 model represents the equivalent geometric scale of a prototype soil field of 9.6 m deep, 21 m long, and 14.6 m wide. A laboratory facility capable of creating such conditions under the normal gravitational condition does not exist. With the use of a centrifuge, we are now able to simulate and measure tsunami-like loading with sufficiently high water pressure and flow velocities. The pressures and flow velocities in the model are identical to those of the prototype yielding realistic conditions of flow-soil interaction.

Metoclopramide and cellular immune functions during polymicrobial sepsis.

Metoclopramide (MCP) has been demonstrated to restore the depressed cellular immune function after hemorrhage by increasing the release of the immunomodulatory pituitary hormone prolactin. We investigated the effect of MCP on serum prolactin concentrations, on cellular immune functions (immune cell distribution, splenocyte proliferation, apoptosis and cytokine release) and on the survival 48 h after induction of a polymicrobial sepsis in mice. Administration of MCP increased circulating serum prolactin concentrations and splenocyte apoptosis rate and improved cellular cytokine release, but did not affect mortality of septic mice. We therefore conclude that administration of MCP modulated splenocyte apoptosis and cytokine release in a murine model of sepsis without an impact on the survival. Furthermore, this effect may be mediated by an increased endogenous prolactin release.

Effects of acute prolactin manipulation on sexual drive and function in males.

The neuroendocrine response to sexual activity in humans is characterized by a pronounced orgasm-dependent increase of plasma levels of prolactin. In contrast to the well-known inhibitory effects of chronic hyperprolactinemia on sexual drive and function, the impact of acute prolactin alterations on human sexual physiology is unknown. Therefore, this study was designed to investigate the effects of acute manipulation of plasma prolactin on sexual behavior. Ten healthy males participated in a single-blind, placebo-controlled, balanced cross-over design. Prolactin levels were pharmacologically increased to high levels (protirelin, 50 micro g i.v.) or reduced to low physiological concentrations (cabergoline, 0.5 mg p.o.). Sexual arousal and orgasm were then induced by an erotic film and masturbation. In addition to continuous neuroendocrine and cardiovascular recordings, the quality and intensity of the acute sexual drive, arousal, orgasm and refractory period were assessed by extensive psychometric measures. Administration of cabergoline decreased prolactin levels and significantly enhanced all parameters of sexual drive (P<0.05), function (P<0.01) and positive perception of the refractory period (P<0.01). Administration of protirelin increased prolactin concentrations and produced small, but not significant reductions of sexual parameters. The sexual effects observed from cabergoline were completely abrogated by coadministration of protirelin. Although different pharmacological sites of action of prolactin-altering drugs have to be considered, these data demonstrate that acute changes in prolactin plasma levels may be one factor modulating sexual drive and function. Therefore, besides a neuroendocrine reproductive reflex, a post-orgasmic prolactin increase may represent one factor modulating central nervous system centers controlling sexual drive and behavior. These findings may offer a new pharmacological approach for the treatment of sexual disorders.

Specificity of the neuroendocrine response to orgasm during sexual arousal in men.

We have demonstrated that sexual activity produces transient sympathoadrenal activation and a pronounced, long-lasting increase in prolactin in men and women. However, by analyzing endocrine alterations at 10-min intervals, a precise assignment of these changes to the pre-, peri- and postorgasmic periods was not possible. Thus, the current study aimed to accurately differentiate the endocrine response to sexual arousal and orgasm in men using an automatic blood collection technique with 2-min sampling intervals. Blood was drawn continuously before, during and after orgasm over a total period of 40 min in 10 healthy subjects and were compared with samples obtained under a control condition. Sexual activity induced transient increases of plasma epinephrine and norepinephrine levels during orgasm with a rapid decline thereafter. In contrast, prolactin levels increased immediately after orgasm and remained elevated throughout the experiment. Although oxytocin was acutely increased after orgasm, these changes were not consistent and did not reach statistical significance. Vasopressin, LH, FSH and testosterone plasma concentrations remained unaltered during sexual arousal and orgasm. These data confirm that prolactin is secreted after orgasm and, compared with oxytocin, seems to represent a more reliable and sustained marker for orgasm in man. The results further reinforce a role for prolactin either as a neuroendocrine reproductive reflex or as a feedback mechanism modulating dopaminergic systems in the central nervous system that are responsible for appetitive behavior.

Acute interferon beta-1b administration alters hypothalamic-pituitary-adrenal axis activity, plasma cytokines and leukocyte distribution in healthy subjects.

It has been suggested that the immune-endocrine communication plays an important role in development and progression of multiple sclerosis (MS). Interferon beta (IFN beta-1b) treatment is the therapy of choice in patients suffering from relapsing remitting or secondary chronic progressive multiple sclerosis. While typical adverse events of IFN beta-1b treatment such as flu-like symptoms or fatigue are well studied, little is known about the acute changes in the immune and neuroendocrine system. Therefore, we analyzed the short-term effects of IFN beta-1b on cortisol, epinephrine, norepinephrine, prolactin and growth hormone (GH) plasma levels before and 4, 8 and 24 h after IFN beta-1b administration in healthy subjects. Moreover, we determined heart rate, blood pressure, body temperature, leukocyte and lymphocyte subsets and plasma levels of interleukin (IL)-1 beta, IL-6, IL-10 and tumor necrosis factor (TNF)-alpha. IFN beta-1b led to an increase in body temperature and heart rate, and in parallel, elevated cortisol, prolactin and GH plasma levels at 4 and 8 h after IFN beta-1b injection. There were no significant alterations in blood pressure, norepinephrine or epinephrine plasma levels. Simultaneously, IFN beta-1b injection led to an immediate granulocytosis while concomitantly decreasing peripheral lymphocytes, especially natural killer (NK) cells. At the same time, IL-6, IL-10 and TNF-alpha plasma levels showed an overall increase. Overall, cytokine administration exerts strong stimulatory effects on the hypothalamic-pituitary-adrenal (HPA)-axis that may contribute to the side effects of IFN beta-1b therapy and affect the efficacy of IFN beta-1b treatment.

Absence of orgasm-induced prolactin secretion in a healthy multi-orgasmic male subject.

In several studies we have recently demonstrated that orgasm induces prolactin secretion in healthy males and females. This suggests that prolactin may form a feedback regulator of the refractory period following orgasm. To examine this position we investigated the prolactin response of a healthy multi-orgasmic male subject. Blood was drawn continuously during masturbation-induced orgasm. The prolactin response of the case-subject was compared with that of nine healthy adult men with a normal refractory period. The case-subject showed no prolactin response to three orgasms. Data from this multi-orgasmic subject support the hypothesized role of plasma prolactin in contributing to sexual-satiation mechanisms.

Adenovirus-mediated Bcl-2 gene transfer inhibits apoptosis and promotes survival of allogeneic transplanted hepatocytes.

BACKGROUND: Donor hepatocyte apoptosis that is induced by host cytotoxic T lymphocytes (CTLs) limits the application of hepatocyte transplantation. Hepatocytes from Bcl-2 transgenic mice can resist the lethal effect of anti-Fas antibody. However, the anti-apoptotic effect of Bcl-2 expression on allogeneic transplanted hepatocytes remains elusive. This study tested the feasibility of Bcl-2 gene transfer as an approach to inhibit CTL-mediated apoptosis in allogeneic transplanted hepatocytes. METHODS: An adenovirus vector that encoded human Bcl-2 gene (AdCMVhBcl-2) was used to transfect cultured rat hepatocytes, which were then transplanted into allogeneic spleens. DNA fragmentation and caspase-3 activation were examined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay and immunohistochemistry for active caspase-3, respectively. Cocultivation of hepatocytes and allogeneic CD8(+) T lymphocytes was performed, and cytotoxicity on hepatocytes was examined by alanine transaminase release. RESULTS: Bcl-2 gene transfer inhibited apoptosis and increased liver-associated enzyme activities in allogeneic transplanted hepatocytes, which were associated with inhibition of caspase-3 activation. Alanine transaminase release in hBcl-2 modified hepatocytes was lower compared with controls, which could not be further decreased by inhibition of Fas ligand and granzyme B. CONCLUSIONS: Adenovirus-mediated Bcl-2 gene transfer blocks CTL-mediated apoptosis in allogeneic hepatocytes by inhibition of caspase-3 activation. Bcl-2 gene transfer could be used to promote survival of transplanted hepatocytes.

Blocking CTL-based cytotoxic pathways reduces apoptosis of transplanted hepatocytes.

BACKGROUND: A major obstacle in allogenic hepatocyte transplantation is increased apoptosis of grafted cells due to CTL-based cytotoxicity. However, whether blockade of Fas- and granzyme-mediated pathways of CTL-based cytotoxicity may provide immune protection to transplanted hepatocytes is poorly defined. Our study aimed to reduce apoptosis of allogenic transplanted hepatocytes by inhibiting granzyme B (GraB) activity and blocking Fas-FasL interaction. MATERIALS AND METHODS: Hepatocyte transplantation was performed by inoculating isolated liver cells from ACI rats (allogenic) or Lewis rats (syngenic) into the spleens of Lewis rats. Recipients were treated with FLIM58, an inhibitory anti-FasL mAb, and GraB inhibitor I alone or a combination of the two drugs for 5 days after transplantation, and were sacrificed at Day 7. Apoptosis of transplanted hepatocytes was detected in situ by TUNEL assay and M30 immunostaining. Glutamate dehydrogenase (GLDH) activity in recipient spleens was examined to evaluate survival of transplanted cells. Recipient spleens were assayed for FasL level with Western blotting and for GraB activity by hydrolysis of GraB substrate. RESULTS: FLIM58 or GraB inhibitor I significantly reduced the percentage of TUNEL-positive and M30-positive hepatocytes and markedly increased GLDH levels in allogenic, but not syngenic, recipient spleens. These effects were more pronounced when the two drugs were used in combination (P < 0.05). Additionally, elevation of FasL and GraB levels in allogenic recipient spleens can be significantly reduced by FLIM58 and GraB inhibitor I, respectively. CONCLUSIONS: Inhibition of GraB activity and blockade of Fas-FasL interaction reduce the apoptosis of allogenic transplanted hepatocytes, and thus improve their survival.

Kupffer cells of cirrhotic rat livers sensitize colon cancer cells to Fas-mediated apoptosis.

Metastasis of colorectal carcinomas rarely occurs in cirrhotic livers. Our study investigated the influence of activated Kupffer cells from cirrhotic rat livers on hepatic colonization and FasR-mediated apoptosis of colon cancer cells. A rat colon cancer cell line, RCN-9, was used to inoculate rat livers. Treatment with conditioned media of Kupffer cells isolated from CCl(4)-induced cirrhotic rat livers (cirrhotic KCM) significantly reduced the incidence of hepatic colonization of RCN-9 cells. In vitro cytotoxicity of Kupffer cells and tumour infiltrating lymphocytes (TILs) on RCN-9 cells was evaluated using [(3)H]-release assay. RCN-9 cells were resistant to cytotoxicity mediated by cirrhotic Kupffer cells, but were sensitized to TIL-mediated killing after treatment with cirrhotic KCM. The specific killing induced by TILs was FasR-mediated, as it was inhibited by ZB4, an antagonistic anti-FasR antibody. In agreement, cirrhotic KCM increased recombinant Fas ligand-induced apoptosis of RCN-9 cells, and up-regulated FasR expression on RCN-9 cells as evaluated by RT-PCR and flow cytometry. These findings suggest that Kupffer cells in cirrhotic livers sensitize metastatic colon cancer cells to FasR-mediated apoptosis by up-regulating the receptors, which thus prepare them to be eliminated by infiltrating lymphocytes.

Coitus-induced orgasm stimulates prolactin secretion in healthy subjects.

Previous data have indicated that orgasm produces marked alterations in plasma prolactin concentrations in men and women. Thus, the current study aimed to extend these data by examining prolactin response to coitus in healthy males and females. Ten pairs of healthy heterosexual couples participated in the study. Blood was drawn continuously for 20 min before, during, and until 60 min following sexual intercourse and orgasm. Plasma was subsequently analysed for prolactin concentrations. Coitus-induced orgasm produced a marked elevation of plasma prolactin in both males and females. Plasma prolactin concentrations remained elevated 1 h following orgasm. These data, together with previous evidence that masturbation-induced orgasm produces pronounced, long-lasting increases in plasma prolactin concentrations in both males and females, suggest a role for acute prolactin alterations in modifying human sexual desire following orgasm.

Migration of naive, effector and memory T cells: implications for the regulation of immune responses.

T cells play an important role in protective immune responses and in the pathogenesis of many diseases. Understanding the mechanisms regulating their distribution in vivo may therefore be of therapeutic value. Reviewing studies that have followed the migration of labelled naive, effector and memory T cells in healthy animals reveals that all T-cell subsets enter all organs investigated. Within the tissue, two principally different migration patterns can be identified. First, naive and memory T cells accumulate in lymphoid organs for about 48 h after injection, as the time needed for migration through lymphoid organs is longer than through non-lymphoid organs. During this time, surface molecule expression is temporarily modified. These changes are reversed before leaving the lymphoid organs and entering the blood to start a new cycle of migration. Second, effector T cells are evenly distributed throughout the body, and most die in the tissues within 24 h. However, depending on the presence of cytokines, some are able to survive and to proliferate, and thereby accumulate in defined microenvironments of the body. Analysing the principles regulating T-cell migration and survival within the tissue may lead to the development of new options for the treatment of disease.

Conditioning in the rat: an in vivo model to investigate the molecular mechanisms and clinical implications of brain-immune communication.

A wealth of in vitro and ex vivo evidence has described both close anatomical interaction and functional bi-directional communication between the immune and central nervous systems (CNS). These data have provided a framework for understanding the physiological mechanisms whereby behavioural factors may impact immune-related disease. An understanding of this interaction, however, as well as verification of the biological relevance of communication among these systems, requires in vivo animal modelling. The development of psychoneuroimmunological models in the laboratory rat has played a key role in advancing the understanding of the influence of behaviour on immune status. One such paradigm is the behavioural conditioning of immune function in the rat. This elegant model is characterised by the ability to examine simultaneously both afferent and efferent brain-immune communication. Specifically, the role of peripheral cytokines in signalling the brain, as well as their anatomical and cellular targets in the CNS, can be identified. On the other hand, the neural and humoral pathways whereby the CNS influences the function and distribution of peripheral immunocytes can be demonstrated, together with the target hormone receptors on immunocompetent cells. Finally, the in vivo biological relevance of brain-immune communication is revealed by behavioural conditioning, demonstrating that clinically relevant conditions such as heart allograft survival can be modified by behavioural processes. Behavioural conditioning thereby provides an excellent example of the utility of in vivo laboratory rat models in psychoneuroimmunology research. Such paradigms not only provide a more complete knowledge of CNS-immune system interaction, but are the platform for determining potential clinical application of this information.

Angiotensin II: a regulator of inflammation during renal disease?

It has been recently recognized that besides its vasoactive actions Angiotensin II (Ang II) exerts various immunomodulatory effects that may contribute to renal injury and to the progression of renal disease. Consistent with this concept, Ang II facilitates macrophage recruitment into the kidney either directly or through the-upregulation of different chemotactic molecules such as RANTES (Regulated on Activation Normal T Expressed and Secreted), monocyte chemoattractant protein-1 (MCP-1) and osteopontin. Infiltrating macrophages not only produce a number of cytokines, growth factors and proinflammatory Mediators, but also synthesize Ang II intacellularly which increases tissue levels of the hormone within the kidney. Finally, specific binding sites for Ang II have been demonstrated on macrophages and increasing evidence indicates that Ang II directly modulates many of the cellular functions of these cells during the course of renal disease. Together these data suggest that Ang II plays an important role in modulating inflammatory responses in the kidney.

Endocrine response to masturbation-induced orgasm in healthy men following a 3-week sexual abstinence.

This current study examined the effect of a 3-week period of sexual abstinence on the neuroendocrine response to masturbation-induced orgasm. Hormonal and cardiovascular parameters were examined in ten healthy adult men during sexual arousal and masturbation-induced orgasm. Blood was drawn continuously and cardiovascular parameters were constantly monitored. This procedure was conducted for each participant twice, both before and after a 3-week period of sexual abstinence. Plasma was subsequently analysed for concentrations of adrenaline, noradrenaline, cortisol, prolactin, luteinizing hormone and testosterone concentrations. Orgasm increased blood pressure, heart rate, plasma catecholamines and prolactin. These effects were observed both before and after sexual abstinence. In contrast, although plasma testosterone was unaltered by orgasm, higher testosterone concentrations were observed following the period of abstinence. These data demonstrate that acute abstinence does not change the neuroendocrine response to orgasm but does produce elevated levels of testosterone in males.

Casino gambling increases heart rate and salivary cortisol in regular gamblers.

BACKGROUND: Although the effects of gambling on cardiovascular parameters have been documented, no data exists describing the effect of gambling on stress hormone secretion. Our study investigated the effect of gambling on heart rate and salivary cortisol in a casino environment. METHODS: Ten male gamblers participated in both an experimental and control session. In the experimental session, gamblers played a game of blackjack using their own money. Gamblers played cards in the same setting during the control condition; however, the game was played for accumulation of points rather than money. Heart rate and endocrine parameters were recorded at baseline, 30 min, and 60 min following commencement of each session, and again at completion of the game. RESULTS: Heart rate increased significantly from baseline to 30 min in the experimental session and remained elevated for the remainder of the recording period. Salivary cortisol was raised at 30 min and further elevated at 60 min during gambling, then returned to control levels following completion of the game. CONCLUSIONS: These data indicate that gambling in a "real life" situation produces increases in salivary cortisol levels that accompany increased cardiovascular activity. Such effects may contribute to the development of gambling addiction.

Influence of alternatively and classically activated macrophages on fibrogenic activities of human fibroblasts.

Activated macrophages regulate fibrogenesis by providing cytokines and growth factors that modulate the proliferation and collagen synthesis of fibroblasts. However, macrophages can be activated in a classical pathway induced by LPS or IFN-gamma and an alternative pathway induced by IL-4 or glucocorticoid. Differently activated macrophages display distinct biological features. To clarify the difference between these two subsets of macrophages in the regulatory mechanisms controlling fibrogenesis, human peripheral blood monocytes were used as the source of macrophages and cocultivation of differently activated macrophages and a fibroblast cell line, WI-38, was performed. Alternatively activated macrophages increased the proliferation index and collagen synthesis of cocultivated WI-38 cells in comparison to untreated monocytes, while classically activated macrophages markedly reduced collagen production of cocultivated WI-38 cells. Additionally, mRNA expression and protein production of TGF-beta(1), PDGF-AA, and PDGF-BB were elevated in alternatively activated macrophages in parallel to their profibrogenic effects. In contrast, expression and production of TNF-alpha, as well as MMP-7, were enhanced in classically activated macrophages. These findings suggested that alternatively activated macrophages enhance fibrogenesis of fibroblasts by providing profibrogenic factors, while classically activated macrophages inhibit fibrogenesis of fibroblasts by releasing antifibrogenic or fibrolytic factors.

Conditioned suppression of contact sensitivity is independent of sympathetic splenic innervation.

The present study investigated the role of sympathetic innervation of the spleen in conditioned suppression of a contact hypersensitivity (CHS) reaction. Behavioral conditioning was achieved by pairing saccharin drinking solution (conditioned stimulus, CS) with injection of cyclosporin A (CsA, 20 mg/kg; unconditioned stimulus, UCS). Four days after sensitization of the animals by application of a 5% 2,4-dinitrochlorobenzene (DNCB) to abdominal skin, the animals were challenged by applying a 1% DNCB solution to the ear. The CHS response was monitored by measuring the degree of ear swelling. Saccharin re-presentation reduced ear swelling to a magnitude that approached that achieved by CsA treatment. Histological examination demonstrated that the conditioned reduction of ear swelling was produced by a reduced leukocyte infiltration of the ear. Prior sympathetic denervation of the spleen did not alter the conditioned suppression of the CHS response. These data indicate that behavioral conditioning using CsA produces alterations of CHS that, unlike conditioned prolongation of heart allograft survival, are independent of sympathetically regulated conditioned alterations in the spleen.

Pavlovian conditioning of immune function: animal investigation and the challenge of human application.

Pavlovian conditioning of immune functions provided early impetus to the rapidly expanding knowledge of bi-directional communication among the immune, endocrine, and central nervous systems. Since these early investigations, the phenomenology of this response has been well characterized. However the neural mechanisms and biological relevance of conditioned immunomodulation remain unclear. To this end, we present here data from our laboratories that have: (1) revealed some of the neural mechanisms and biological relevance of an animal model of conditioned immunomodulation; (2) demonstrated the conditionability and potential mechanisms of conditioned immune responses in healthy humans, and (3) investigated conditioned immunomodulation in a clinical sample. Together, these data demonstrate that animal models provide a basis for investigating mechanisms whereby conditioned changes in immune function may modulate health status in a clinical realm.

Neuroendocrine response to film-induced sexual arousal in men and women.

The psychoneuroendocrine responses to sexual arousal have not been clearly established in humans. However, we have demonstrated previously that masturbation-induced orgasm stimulates cardiovascular activity and induces increases in catecholamines and prolactin in blood of both males and females. We presently investigated the role of orgasm in producing these effects. Therefore, in this study parallel analysis of prolactin, adrenaline, noradrenaline, and cortisol concentrations, together with cardiovascular variables of systolic/diastolic blood pressure and heart rate were undertaken during film-induced sexual arousal in nine healthy adult men and nine healthy adult women. Blood was drawn continuously via an indwelling cannula and connected tubing system passed through a mini-pump. In parallel, the cardiovascular parameters were recorded continuously via a computerised finger-cuff sensor. Subjective sexual arousal increased significantly in both men and women during the erotic film, with sexual arousal eliciting an increase in blood pressure in both males and females, and plasma noradrenaline in females only. In contrast, adrenaline, cortisol and prolactin levels were unaffected by sexual arousal. These data further consolidate the role of sympathetic activation in sexual arousal processes. Furthermore, they demonstrate that increases in plasma prolactin during sexual stimulation are orgasm-dependent, suggesting that prolactin may regulate a negative-feedback sexual-satiation mechanism.

Conditioned alterations of specific blood leukocyte subsets are reconditionable.

Behavioral conditioning has the ability to produce changes in immune function. However, it is unknown whether conditioned changes of immune function can be recalled on multiple occasions. To address this issue we paired a novel saccharin drinking solution with intraperitoneal cyclosporin A (CsA) injection in rats. Saccharin re-presentation produced a reduction in splenocyte proliferation that mirrored the effect of CsA. Such functional changes were paralleled by a significant conditioned leukopenia in peripheral blood, which opposed the leukocytosis induced by CsA. Using the conditioned leukopenia in blood as a 'diagnostic window' of conditioned immunosuppression, the maintenance of CsA-induced changes was investigated by examining blood samples collected repeatedly. Experiments on the same group of animals over a period of 1 year showed that the conditioned leukopenia was reproducible on multiple occasions by reimplementing either the whole conditioning paradigm or reexposure to the saccharin solution only. These results demonstrate that behaviorally conditioned alterations of immune parameters are maintained in subsequent trials, indicating the potential clinical feasibility of behavioral conditioning procedures.