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A Ayala

Publications and source records attributed to A Ayala.

At least 145 records · Page 8Linked to original sources
PubMed1995

Changes in the histidine residues of Cu/Zn superoxide dismutase during aging.

Cu/Zn-Superoxide dismutase activity (Cu/Zn-SOD) was studied in liver from 3- and 24-month-old rat. A significant decrease of enzyme activity in liver of the aged rat was found. Various amino acid residues and protein carbonyl groups (CO) were measured in purified young and old enzyme. It was found that the 'old' enzyme had one histidine fewer and higher CO content than the 'young' Cu/Zn-SOD. Inactivation 'in vitro' of purified commercial bovine erythrocyte Cu/Zn-SOD led to a decrease in the enzymatic activity, an increase in the CO and one histidine residue modified. A similar behavior between aging and oxidation was suggested.

Aging↗
PubMed1995

Does endotoxin play a major role in inducing the depression of macrophage function during polymicrobial sepsis?

BACKGROUND: Endotoxin (ETX) is thought to be the primary inducer of proinflammatory mediator release associated with bacterial sepsis. Furthermore, a number of studies indicate that preexposure of animals to high doses of ETX produces macrophages (M luminal diameters) that are refractory to ex vivo stimulation with ETX. However, it is unknown if levels of ETX comparable to those typically encountered in sepsis induce a similar refractory state in M luminal diameters. DESIGN: To assess this, peritoneal M luminal diameters (PM luminal diameters) were harvested from C3H/HeN mice (ETX sensitive) at 1 hour (early) or 24 hours (late) following cecal ligation and puncture (CLP) to induce polymicrobial sepsis, sham CLP, or laparotomy followed by peritoneal implantation of a minipump delivering either saline or ETX (0.025 microgram/g of body weight, every 24 hours). Peritoneal M luminal diameter cultures were incubated with ETX, either 0 or 10 micrograms/mL, for 24 hours, and their ability to release interleukin-1, interleukin-6, and tumor necrosis factor was assessed by bioassay. RESULTS: Chronic low-dose ETX with 0 microgram of ETX media added produced early (at 1 hour) in vivo activation of PM luminal diameter interleukin-1 release, which was comparable to that seen in mice subjected to CLP. However, unlike PM luminal diameter taken from CLP mice, PM luminal diameters from mice implanted with the ETX minipump at 1 or 24 hours showed no marked decline in their ability to respond to ETX (10 micrograms). Comparable changes were seen for interleukin-6 and tumor necrosis factor release. CONCLUSIONS: Bacterial component(s) other than ETX per se induces the sustained dysfunction in PM luminal diameter capacity to produce proinflammatory cytokines during sepsis and/or peritonitis. Thus, agents directed against ETX alone may not be adequate in the treatment of polymicrobial sepsis.

Animals↗
PubMed1995

Increase in dopamine turnover and tyrosine hydroxylase enzyme in hippocampus of rats fed on low selenium diet.

We have studied the turnover of dopamine, noradrenaline, and serotonin and their metabolites in hippocampus of adult female rats that were fed control or selenium-deficient diets during 15 days. Under these circumstances, there was an increase of dopamine turnover (4-fold) in rats fed with selenium-deficient diet with respect to controls and also an increase in the tyrosine hydroxylase activity (75.8%), which was the result of the increase of the amount of the enzyme (2-fold), without significant change in the phosphorylation of the tyrosine hydroxylase. In addition the glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase activities have been studied. After selenium-deficient diet, the enzymatic activities of superoxide dismutase and catalase did not show change with respect to the controls; however glutathione reductase and glutathione peroxidase significantly decreased 15% and 29%, respectively. It is concluded that the increase in dopamine turnover seems to be associated with the induction of tyrosine hydroxylase enzyme. In these conditions the decrease in antioxidant capacity may produce a cascade of events, which accelerates the degenerative process, since the increase in dopamine turnover produces an increase in oxygen radical by monoamine oxidase activity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Cytokine gene expression in splenic macrophages and Kupffer cells following haemorrhage.

TNF-alpha, IL-1, IL-6 and TGF-beta are important macrophage-derived mediators which play the pleiotropic role in inflammatory, metabolic, hematopoietic and immunologic processes. Studies have shown that haemorrhagic shock without significant tissue trauma induces profound immunosuppression which is associated with elevated plasma levels of TNF-alpha IL-1, IL-6 as well as TGF-beta. Furthermore, Kupffer cells but not the splenic M phi isolated from post-haemorrhaged animals showed an increased capacity to release inflammatory cytokines in response to LPS stimulation in vitro. However, it remains unknown whether the innate (i.e. in the absence of LPS stimulation) cytokine genes expression in Kupffer cells and splenic M phi is affected by haemorrhage. To determine this, C3H/HeN male mice were bled to and maintained at a mean arterial blood pressure of 35 mmHg for 60 min, and then adequately resuscitated. Splenic macrophages and Kupffer cells were isolated at 1 h after haemorrhage. Total RNA was extracted and cytokine mRNA was detected by semi-quantitative reverse transcription and polymerase chain reaction (RT-PCR). The results demonstrate that haemorrhage significantly elevated the mRNA accumulation of TNF-alpha, IL-1 beta, TGF-beta while IL-6 gene expression in Kupffer cells and splenic M phi was only slightly increased. Since Kupffer cells but not the splenic M phi showed increased cytokine release, it could be concluded that the differential regulation of cytokine release by these two macrophage populations following haemorrhage may be due to the divergence of the cytokine at the translational level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Hemorrhage affects the ability of murine peritoneal macrophages to alkanize intracellular pH in acidic environments.

Although departures from the normal physiologic pH range, associated with states of shock, injury, and/or infection are thought to impair phagocytic function and chemotaxis, it remains unknown if the ability of the peritoneal macrophage (pMø) to gate H+ is affected following hemorrhagic shock. To study this, male C3H/HeN mice were bled to a BP of 40 mm Hg and maintained at that level for 1 hr. Following resuscitation with the shed blood plus 2x that volume as Ringer's lactate, pMø was harvested via lavage in bicarbonate-free RPMI 1640 and enumerated to 2 million cells/ml. PMø was then loaded with a pH-sensitive dye, BCECF (2 micrograms/ml), for 20 min and washed with a buffered Na+ solution followed by phorbol myristate acetate stimulation (0.5 micrograms/ml). The capacity of the pMø to gate H+ at an external pH of 7.35 or 6.7 was assessed via fluorescence spectrophotometry. PMø from hemorrhaged animals had a decreased ability to alkalinize intracellular pH compared to that of control (P < 0.05), indicating a decreased ability of these Mø to maintain internal pH in an acidic environment following hemorrhage. In additional studies, oxidative burst capacity was determined by employing a commercially available fluorogenic substrate, (Fc Oxiburst), which fluoresces during intracellular oxidation. Fluorescence (U x 10(6)) was assessed with the ACAS 570 laser cytometer, after 0 and 200 sec following ingestion of substrate. The results demonstrate that pMø oxidative burst capacity was also decreased following hemorrhage and resuscitation.

Adenosine Triphosphate↗
PubMed1995

A novel nonanticoagulant heparin improves splenocyte and peritoneal macrophage immune function after trauma-hemorrhage and resuscitation.

Recent studies have shown that heparinization of animals prior to or even after hemorrhagic shock improves tissue perfusion and organ function. However, the anticoagulant properties of conventional heparin preclude its clinical use in trauma care. The aim of our study, therefore, was to determine whether chemically modified heparin, i.e., a novel nonanticoagulant heparin (GM1892), which does not have significant anticoagulant activity (approximately 2% of the anticoagulant activity of conventional heparin), produces any beneficial effects on splenocyte and macrophage immune function following trauma-hemorrhage and resuscitation. To determine this, following the induction of tissue trauma (i.e., a midline laparotomy), mice were bled to and maintained at a mean arterial pressure of 35 mm Hg for 1 hr. The animals then received GM1892 (7 mg/kg body wt), conventional heparin (7 mg/kg body wt), normal saline prior to resuscitation with three times the volume of shed blood with Ringer's lactate. Two hours after resuscitation the animals were sacrificed, splenocytes were isolated, and splenic, as well as peritoneal macrophage, cultures were established. The ability of the splenocytes to release IL-2 and IL-3 in response to mitogen was markedly improved in hemorrhaged animals which were treated with GM1892 or conventional heparin compared to saline-treated mice. Furthermore, the capacity of splenic and peritoneal macrophages to release IL-6 was restored in the hemorrhaged animals that received GM1892 or conventional heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

PAF-antagonist administration after hemorrhage-resuscitation prevents splenocyte immunodepression.

A number of studies have suggested that the inflammatory and chemotactic autocoid platelet activating factor (PAF), together with various cytokines, plays an important role in the pathophysiology of trauma, sepsis, and shock. However, little is known about PAF's contribution to the immunosuppression associated with hemorrhage. The aim of our study was, therefore, to determine if the use of a PAF-antagonist following hemorrhage has any salutary effects on splenocyte lymphokine production. To study this, mice were bled to and maintained at a mean arterial pressure of 35 mm Hg for 60 min. The mice were then segregated into three groups and were resuscitated with shed blood plus lactated Ringer's solution (2x the volume of shed blood), containing either a potent PAF-antagonist (Ro 24-4736, a thienodiazepine) in dimethyl sulfoxide (DMSO) or DMSO-vehicle. Sham-operated mice received either DMSO-vehicle in saline or saline alone. Twenty-four hours thereafter the animals were sacrificed and splenocyte cultures established and stimulated for 48 hr with Con A (2.5 micrograms/ml). Supernatant lymphokine levels were determined by bioassay. The cellular release of interleukin-2 and -3 (IL-2 and IL-3) by splenocytes was significantly depressed in the nontreated or vehicle-treated hemorrhaged animals compared to shams. Treatment with the PAF-antagonist Ro 24-4736 restored IL-2 and IL-3 release values to levels comparable to those of the sham-operated animals. Thus, (1) PAF appears to play a significant role in hemorrhage-induced immunosuppression and (2) the use of a PAF-antagonist to uncouple the PAF-generated feedback loops prevents the depression in splenocyte function following hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of hydroxyethyl starch after trauma-hemorrhagic shock: restoration of macrophage integrity and prevention of increased circulating interleukin-6 levels.

OBJECTIVES: To determine the effects of resuscitation with the colloidal solution (hydroxyethyl starch) vs. crystalloid solution on cell-mediated immune functions after trauma-hemorrhage. DESIGN: Prospective, multiexperimental, randomized, controlled study. SETTING: University research laboratory. SUBJECTS: Thirty-six inbred male C3H/HEN (endotoxin-sensitive) mice, aged 6 to 7 wks, and weighing 18 to 23 g. INTERVENTIONS: Crystalloid (lactated Ringer's solution) with and without 6% hydroxyethyl starch after trauma-hemorrhage. MEASUREMENTS AND MAIN RESULTS: Mice underwent laparotomy, were bled to and maintained at a blood pressure of 40 mm Hg for 60 mins, then resuscitated with either 4x the shed blood volume as lactated Ringer's solution or 2x the shed blood volume as lactated Ringer's solution plus 1 x 6% hydroxyethyl starch. Sham mice were neither hemorrhaged nor resuscitated. At 2 or 24 hrs posthemorrhage, serum, splenocytes, peritoneal macrophages, and splenic macrophages were obtained. Bioassays were used to determine interleukin-2, interleukin-3, and interleukin-6 concentrations, while splenocyte proliferation was assessed by 3H-thymidine incorporation. Trauma-hemorrhage markedly depressed splenocyte proliferation, interleukin-6 release by macrophages, and lymphokine release at 2 and 24 hrs postresuscitation. The combination of lactated Ringer's solution and hydroxyethyl starch neither restored, nor exacerbated lymphocyte functions. Interleukin-6 release by peritoneal macrophages was restored 24 hrs after hydroxyethyl starch infusion; serum interleukin-6 concentrations remained at sham levels. CONCLUSIONS: Since the use of lactated Ringer's solution and hydroxyethyl starch after hemorrhage did not adversely affect cell-mediated immune functions, but produced salutary effects on macrophage functions, hydroxyethyl starch is a safe and beneficial resuscitation adjunct.

Animals↗
PubMed1995

Effect of surgical trauma on splenocyte and peritoneal macrophage immune function.

Although previous studies have shown that simple laparotomy produces a depression in peritoneal macrophage (Mphi) antigen presentation capacity, it remains unknown whether the adverse effects of laparotomy are limited to peritoneal Mphi or whether such an insult also affects splenocyte immune function. To study this, mice were anesthetized and a 1-inch midline abdominal incision was made, followed by abdominal closure. At 2 and 24 hours after the surgical procedure, the animals were killed, splenocyte cultures established and stimulated for 48 hours with concanavalin A (2.5 micrograms/mL), while peritoneal macrophage cultures were stimulated with LPS (10 micrograms/mL). The proliferative capacity of the splenocytes, as well as their ability to release interleukin-2 and interleukin-3, was markedly decreased at 2 as well as 24 hours after laparotomy. Furthermore, the release of interleukin-6 by splenic and peritoneal macrophages from animals that underwent laparotomy were also significantly depressed at both 2 and 24 hours. These results support the concept that surgical stress in the form of midline laparotomy per se is sufficient to produce a significant impairment in cell-mediated immunity, thus setting the stage for increased incidence of postoperative complications.

Animals↗
PubMed1995

The induction of accelerated thymic programmed cell death during polymicrobial sepsis: control by corticosteroids but not tumor necrosis factor.

Thymic programmed cell death (PCD) or apoptosis (Ao) is elevated during inflammation by a variety of stressors in vitro (i.e., glucocorticoids, tumor necrosis factor (TNF), prostanoids, etc.), however, little or no information is available concerning its presence in polymicrobial sepsis. To establish whether or not PCD is accelerated in the thymus following the onset of sepsis, thymocytes were harvested from C3H/HeN mice at 1, 2, 12, and 24 h following cecal ligation and puncture (CLP; to induce sepsis) or Sham-CLP (Sham), and assessed for changes in thymocyte viable cell yield, increased Ao + cells based on FACS analysis (propidium iodide staining) or by evidence of fragmentation of the genomic DNA. The results indicate that at 1 h post-CLP there were no marked changes in any of these parameters. However, by 4 h post-CLP the percentage of Ao + thymocytes increased and the septic mouse genomic DNA exhibited trace amounts of fragmentation. These changes increased in the septic animals cells through both 12 and 24 h. Alternatively, thymic viable cell yield did not significantly decrease until 12 h. Marked changes in systemic mediators, corticosterone and TNF, were also detected in septic mouse blood at all time points. In an effort to determine the contribution of these two agents to the induction of the accelerated PCD seen here, mice were randomized to receive either RU-38486 (11 beta-[p-(dimethylamino)phenyl]-17 beta-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one (Mifepristone); a steroid receptor blocker), polyethylene glycol (PEG)-(rsTNF-R1)2 (a TNF inhibitor) immediately following CLP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
PubMed1995

Trauma-hemorrhage causes prolonged depression in cellular immunity.

A number of clinical studies have shown that multiple and severe trauma causes immunosuppression and increases the susceptibility to sepsis. However, because there is a close temporal relationship between trauma and hemorrhage in humans, it is difficult to dissociate the effects of tissue trauma versus hemorrhage on immunity in the clinical setting. Studies in mice have shown that simple hemorrhage per se as well as laparotomy alone produces a marked depression in cellular immunity and no difference was seen in the extent of depression at 2 h if these two insults were combined. Nonetheless, it remains unknown whether the combined model of trauma-hemorrhage produces a more protracted depression in immune function. To study this, 5 days after either sham operation, laparotomy (i.e. trauma), hemorrhage alone (35 mmHg for 1 h, followed by resuscitation), or the combination of laparotomy and hemorrhage, mice (C3H/HeN) were sacrificed, after which splenocyte and peritoneal macrophage cultures were established. The proliferative capacity of the splenocytes, as well as their ability to release IL-2 and IL-3, was markedly decreased in the trauma-hemorrhage animals but was normal in the other groups. Furthermore, the release of IL-6 by peritoneal macrophages from animals that underwent trauma-hemorrhage was also significantly depressed. These results support the concept that traumatic injury in the form of a midline laparotomy combined with hemorrhage produces a more protracted impairment in cell-mediated immunity than laparotomy or hemorrhage alone.

Animals↗
PubMed1995

Hypoxemia in the absence of blood loss or significant hypotension causes inflammatory cytokine release.

Although hemorrhagic shock causes a significant elevation of circulating levels of proinflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6], it remains unknown whether hypoxemia per se in the absence of blood loss activates macrophages (Mø) to release increased amounts of these mediators. To study this, hypoxemia was induced in C3H/HeN mice by placing them in a plastic box that was flushed with a gas mixture containing 95% N2-5% O2 for 60 min, followed by return of the mice to room air. For control animals, the plastic box was flushed with room air. At 0, 2, or 24 h thereafter, blood samples were obtained, plasma was separated, and then peritoneal Mø (pMø) and Kupffer cells (KC) were isolated and incubated at 37 degrees C for 24 h with lipopolysaccharide. The Mø supernatants, as well as plasma samples, were assayed for TNF-alpha, IL-1 beta, and IL-6 with the use of specific bioassays. Hypoxemia induced a significant (P < 0.05) increase in plasma TNF-alpha levels during the entire study period while circulating IL-6 was elevated by 313% (P < 0.01) at 24 h after hypoxemia compared with shams. Moreover, the release of TNF-alpha, IL-1 beta, and IL-6 by pMø and KC was markedly increased after hypoxemia compared with shams. Thus, hypoxemia in itself, in the absence of any blood loss or tissue injury, induces release of proinflammatory cytokines, which may contribute to systemic inflammation following hypoxemia.

Animals↗
PubMed1995

Sentinel lymph node dissection for penile carcinoma: the M. D. Anderson Cancer Center experience.

PURPOSE: We determined whether an extended sentinel lymph node dissection is effective for staging penile squamous carcinoma associated with clinically negative inguinal lymph nodes. MATERIALS AND METHODS: A retrospective review was done of 20 consecutive patients who underwent extended sentinel lymph node dissection between 1985 and 1994. RESULTS: Of the patients 14 underwent bilateral extended sentinel lymph node dissection, and 6 underwent ipsilateral extended sentinel lymph node dissection plus contralateral inguinal or ilioinguinal lymphadenectomy. All lymph nodes included in the extended sentinel node dissection were negative for metastases. Five patients had inguinal metastases at a median of 10 months (range 3 to 21) after negative extended sentinel lymph node dissection. CONCLUSIONS: Although it is a more extensive procedure than sentinel lymph node biopsy, extended sentinel lymph node dissection is still associated with a significant false-negative rate (25%). Thus, its routine use can no longer be recommended.

Adult↗
PubMed1995

[Hypophosphatemic osteomalacia acquired after renal transplantation: a a cause of severe osteoporosis].

Renal osteodystrophy improves after renal transplantation but, after the procedure, other forms of bone disease emerge. We report a male patient that received a renal allograft four years before, who consulted for low back pain secondary to multiple vertebral compression fractures. The patient had good renal function, a parathormone independent hyperphosphaturia, normal 25-OH cholecalciferol, increased urinary hydroxyproline, decreased osteocalcin, reduced bone density and a bone biopsy revealing osteomalacia. The diagnosis of hypophosphatemic osteomalacia was reached and treatment with phosphates and ergocalciferol was started but, despite this, the patient suffered a new fracture two years later. Two mechanisms can produce hypophosphatemia after a renal transplantation: a parathormone excess due to the previous renal failure, that disappears during the first year after the transplantation or a derangement in renal phosphate transport that can be due to a generalized proximal tubule solute transport derangement (Fanconi syndrome), parathormone hypersensitivity or to an "idiopathic" hyperphosphaturia. Despite a good treatment, bone mass is not recovered and there is a high fracture risk. Mineral metabolism must be closely monitored after a renal allograft and its alterations must be quickly treated.

Adult↗
PubMed1995

The role of bacterial translocation on Kupffer cell immune function following hemorrhage.

Studies have shown that Kupffer cell and splenic macrophage, as well as peritoneal macrophage antigen presentation function, was significantly depressed following hemorrhage and remained so for at least 96 hours after resuscitation. Although macrophage antigen presentation was depressed, in all the cell populations studied, it was only the Kupffer cells which were upregulated to produce increased inflammatory cytokines. Furthermore, Kupffer cells from hemorrhaged animals exhibited enhanced, as opposed to reduced toxicity by peritoneal and splenic macrophages. This correlated well with increased cell-associated TNF on Kupffer cells. as well as increased capacity of Kupffer cells to release inflammatory cytokines after hemorrhage. It, therefore, could be postulated that while the enhanced Kupffer cell cytotoxicity may be beneficial in the destruction of pathogens seen in the liver due to bacterial translocation, this same activity may also contribute directly or indirectly to hepatocellular dysfunction and injury which is seen following hemorrhagic shock. Nonetheless, the depression in various immune functions after hemorrhage and resuscitation was comparable in both endotoxin-tolerant and -intolerant mice. Thus, it is debatable whether the alterations in immune function seen after hemorrhage are primarily due to the release of endotoxin into the blood stream during and/or following the hemorrhagic insult. Although translocation and/or endotoxemia occurs following severe hemorrhage, endotoxin may not be the sole or primary agent responsible for the induction of immunodepression after hemorrhage. The depressed Kupffer cell functions and increased inflammatory cytokine release by these cells can be significantly improved by post-treatment of animals with chloroquine, ibuprofen, diltiazem or ATP-MgCl2. Thus, these agents offer new therapeutic modalities in restoring the depressed Kupffer cell immune functions and in the treatment of generalized immunosuppression, as well as for decreasing the susceptibility to sepsis which is observed following severe blood loss.

Animals↗