Significant reduction of 125 I-meta-iodobenzylguanidine accumulation directly caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine, a toxic agent for inducing experimental Parkinson's disease

A significant reduction of cardiac 123I-meta-iodobenzylguanidine (MIBG) accumulation has been reported in patients with idiopathic Parkinson's disease. However, it is unclear whether this reduction in cardiac sympathetic nerve is caused primarily or secondarily to the degeneration of sympathetic nerve centres which occurs in Parkinson's disease. Therefore, we examined neuronal 125I-MIBG accumulation in mice hearts of an experimental Parkinson's disease model and in sympathetic cells without any neuronal innervation. Cardiac accumulation of 125I-MIBG was determined 4h after intravenous injection of 125I-MIBG in mice pretreated with 1-methyl-4-phenyl-1,2,3,6-tetrahydroxypyridine (MPTP), an inducer of Parkinson's disease. In an in vitro study, uptake of 125I-MIBG was determined in a cultured pheochromocytoma cell line (PC-12), which was pretreated with MPTP. MPTP reduced MIBG accumulation mainly in its neuronal component of mice hearts, suggesting that MPTP impairs cardiac sympathetic nerves to uptake MIBG. Application of MPTP also caused near-complete blockade of 125I-MIBG accumulation in PC-12 cells. In the experimental PD models, it was shown that neuronal accumulation of MIBG was impaired by the direct action of MPTP to the sympathetic cells. These findings support the idea that cardiac sympathetic nerves are primarily impaired in Parkinson's disease despite the presence or absence of systemic autonomic failure.

Development of instruments to measure appraisal of care among Japanese family caregivers of the elderly

The purpose of this study was to develop two instruments for the evaluation of positive and negative appraisal of care among family caregivers of elderly Japanese care recipients within the framework of caregiver adaptation. The positive appraisal of care instrument (PAC) includes domains of relationship satisfaction, role confidence, consequential gain, and normative fulfillment. The negative appraisal of care instrument (NAC) includes domains of role exhaustion, isolation, relationship difficulty, and symptom management difficulty. The PAC and NAC are self-administered questionnaires and were developed from data collected from 337 family caregivers of relatives aged 65 years and over who were using visiting nursing services from 21 organizations in multiple areas of Japan. Out of 87 items, 21 PAC items and 14 NAC items were selected based on content and construct validity and internal consistency examination. Results show evidence of validity and reliability for the PAC and NAC, although some NAC domains may benefit from further refinement. The PAC and NAC will be useful research tools for examining elder caregiving experience and evaluating nursing care for elders.

Reversible hypophosphatemia during moderate hypothermia therapy for brain-injured patients

OBJECTIVE

Because plasma potassium, which may similarly change as plasma phosphate (P), decreases during moderate hypothermia, plasma P, a requisite electrolyte for the cell function, may alter during therapeutic moderate hypothermia for brain-injured patients. In 22 such patients who underwent moderate hypothermia or were treated with normothermia, plasma concentrations of P and other chemicals were examined.

DESIGN

A prospective study.

SETTING

The intensive care unit of a medical university hospital.

PATIENTS AND INTERVENTIONS

In 15 consecutive patients with brain injury who underwent moderate hypothermia and 7 serial patients treated with normothermia, plasma concentrations of P, potassium, glucose, blood gas tension and pH, daily urine volume, and water balance were examined. Inequality in the numbers of patients of the two groups was the result of patient exclusion because of multiple trauma, aluminum hydroxide administrations, hyperventilation, preexisting diabetes mellitus, or administration of insulin. Daily blood sampling was done around 8 am. Inclusion criteria included a Glasgow Coma Scale score assessment < or = 8 at admission to the emergency room and evidence of injury on computerized tomography scanning of the brain.

MEASUREMENT AND MAIN RESULTS

Hypothermia decreased plasma P levels as compared with those of normothermia within 4 days after the injury (this period was similar to the duration of the hypothermic phase in the hypothermia group). Such reduction related to changes in blood glucose levels, but not to any in the urine volume, or water balance. The P decrease occurred during the hypothermic phase, but subsequently there was a recovery of P after the rewarming phase. The changes in plasma potassium levels were similar to those in plasma P concentrations during the course. Such changes were accompanied by a recovery of decreased heart rate that occurred during the hypothermic phase.

CONCLUSION

The results suggest that moderate hypothermia of 32-33 degrees C decreases plasma P levels. Further studies are required to examine whether P repletion may overcome certain hemodynamic derangements during moderate hypothermia in brain-injured patients.

[A case of non-invasive pulmonary aspergillosis that rapidly deteriorated]

The pulmonary diseases caused by the Aspergillus species include invasive forms, for example, invasive pulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, and non-invasive pulmonary aspergillosis. Though these forms are defined pathologically by the presence of the Aspergillus species that invades the lung tissue, they are used as clinical entities. We report a case of non-invasive pulmonary aspergillosis which, from the clinical data, appeared likely to be misdiagnosed as the chronic invasive form. A 45 year-old man received chemoradiotherapy for lung cancer as well as undergoing an left upper lobectomy. Two weeks after the surgery the patient developed a cough, high fever and chest pain. Chest radiography and chest computed tomography showed a rapidly enlarging cavity with an internal mass and infiltration in the left lower lung field. A transbronchial biopsy specimen of the cavity wall showed fungal hyphae. Bronchial washing culture grew Aspergillus fumigatus. Itraconazole and amphotericin B were administered, but the patient's condition did not improve. A left lower lobectomy was performed. The histologic findings showed that the fungal hyphae were only on the surface of the cavity wall, and were surrounded by necrosis and widespread inflammatory cell infiltration. No fungal invasion of the viable lung tissue was seen. The area of infiltration revealed an organizing pneumonia without Aspergillus or other organisms. Our final diagnosis was non-invasive pulmonary aspergillosis. There has been no recurrence of the lung cancer or of the pulmonary aspergillosis in the three years since surgery. It is reported that non-invasive pulmonary aspergillosis passes through a period so active that it seems to be the invasive form for its entire clinical course. To avoid confusion in diagnosis, establishment of a comprehensive clinical classification of pulmonary aspergillosis will be needed.

[Pneumonia caused by Nocardia nova]

This is the first clinical report of a case of pneumonia caused by Nocardia nova in Japan. A 52 year-old woman who had received steroids and cyclophosphamide for six years because of polymyositis was admitted to our hospital for further examination. On admission she had a mild cough, and her chest radiography and computed tomography revealed bilateral multiple nodules, some of which were cavitated. She developed a cough productive of yellow sputum and fever up to 38 degrees C. Examination of the sputum revealed a gram-positive branched organism and sputum cultures repeatedly grew Nocardia species. The isolate was identified as Nocardia nova later. Clinical recovery was obtained readily upon treatment with imipenem and trimethoprim methoxazole, though the latter drug was discontinued because of nausea and anorexia. This drug was therefore replaced with oral minocycline, which proved to be ineffective clinically although susceptibility testing of the drug showed positive sensitivity. Minocycline was replaced with clarithromycin, after which chest radiography and computed tomography showed almost total resolution of the infiltrates. Clarithromycin may be an alternative oral agent to sulfonamides or minocycline when these agents are ineffective or not tolerated.

3-Hydroxyanthranilic acid, an L-tryptophan metabolite, induces apoptosis in monocyte-derived cells stimulated by interferon-gamma

3-Hydroxyanthranilic acid (3-HAA), a metabolite of L-tryptophan, accumulates in monocyte-derived cells (THP-1), but not in other cell lines tested (MRC-9, H4, U373MG, Wil-NS), following immune stimulation that induces indoleamine-2,3-dioxygenase (IDO), a rate-limiting enzyme in the L-tryptophan kynurenine pathway. We examined whether metabolites of the L-tryptophan-kynurenine pathway act to induce apoptosis in monocytes/macrophages. Of the L-tryptophan metabolites tested, only 3-HAA at a concentration of 200 micromol/L was found to induce apoptosis in THP-1 and U937 cells. The addition of ferrous or manganese ions further enhanced apoptosis and free radical formation by 3-HAA in these two types of cells. The apoptotic response induced by 3-HAA was significantly attenuated by the addition of antioxidant, alpha-tocopherol or Trolox (a water-soluble analogue of vitamin E), and the xanthine oxidase inhibitor, allopurinol. In addition, the 3-HAA-induced apoptotic response was slightly attenuated by catalase, but not by superoxide dismutase (SOD), indicating that generation of hydrogen peroxide is involved in this response. Interferon-gamma (IFN-gamma), an inducer of IDO, potently induced apoptosis in THP-1 cells, but not in U937 cells, in the presence of ferrous or manganese ions. This different susceptibility to apoptosis inducer between THP-1 and U937 cells may depend on the capacity of the cells for 3-HAA synthesis following IDO induction by IFN-gamma. Furthermore, apoptosis was suppressed by cycloheximide in THP-1 cells, suggesting that newly synthesized proteins may be essential for apoptotic events. These results suggest that 3-HAA induces apoptosis in monocytes/macrophages under inflammatory or other pathophysiological conditions.

Activation of Fc epsilon RI-positive eosinophils in bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune disease frequently occurring in elderly persons. It has been reported that 92-kDa gelatinase released from eosinophils cleaves the extracellular domain of BP180 protein, suggesting a direct role of eosinophils in bulla formation in this disease. The expression of the high-affinity IgE receptor, Fc epsilon RI, on eosinophils was examined in patient with BP. Samples of affected skin obtained from 7 patients with BP were stained immunohistochemically by the alkaline phosphatase anti-alkaline phosphatase (APAAP) method and mirror sections were examined. Eosinophils were present at a rate of 1.0-19.0% in lesions of the dermis, and the number of IgE-positive cells exceeded that of Fc epsilon RI-positive cells in all cases. These cells were not detected in the epidermis, and examination of mirror sections confirmed that the Fc epsilon RI-positive cells corresponded to eosinophils. It has been demonstrated that Fc epsilon RI-positive cells are involved in the dermal lesions of BP. The activation of eosinophils by Fc epsilon RI may participate in the pathogenesis of BP by triggering the degranulation of mast cells.

Diclofenac and flurbiprofen with or without clonidine for postoperative analgesia in children undergoing elective ophthalmological surgery

We conducted a prospective, randomized study to compare the efficacy of preoperative diclofenac, flurbiprofen, and clonidine, given alone, as well as the combination of diclofenac and clonidine, and flurbiprofen and clonidine in controlling postoperative pain in 125 children. The patients (ASA I, 2-12 years) undergoing elective ophthalmological surgery were allocated to one of five groups: rectal diclofenac 2 mg.kg(-1) following oral placebo premedication, i. v. flurbiprofen 1 mg.kg(-1) following placebo premedication, oral clonidine premedication, rectal diclofenac 2 mg.kg(-1) following clonidine, and i.v. flurbiprofen 1 mg.kg(-1) following clonidine. The children received clonidine (4 microg.kg(-1)) or placebo 105 min before anaesthesia. Diclofenac or flurbiprofen was given immediately after induction of anaesthesia. Anaesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using a modified objective pain scale (OPS). No opioids were administered throughout the study. Rectal diclofenac 2 mg.kg(-1) i.v. flurbiprofen 1 mg.kg(-1), oral clonidine 4 microg.kg(-1) provided similar OPS scores and requirement for supplementary analgesics during 12 h after surgery. Combination of oral clonidine and one of these nonsteroidal analgesics minimized postoperative pain. Our findings suggest that this combined regimen may be a promising prophylactic approach to postoperative pain control in children undergoing ophthalmological surgery.

Tumor necrosis factor-alpha (TNF-alpha) plays a protective role in acute viralmyocarditis in mice: A study using mice lacking TNF-alpha

BACKGROUND

It has been reported that tumor necrosis factor-alpha (TNF-alpha) is expressed in the heart with viral myocarditis and that its expression aggravates the condition. The pathophysiological effects of TNF-alpha on viral myocarditis, however, have not been fully elucidated.

METHODS AND RESULTS

To investigate the role of TNF-alpha in the progression of viral myocarditis, we used TNF-alpha gene-deficient mice (TNF-alpha(-/-)) and induced acute myocarditis by infection with encephalomyocarditis virus (EMCV). The survival rate of TNF-alpha(-/-) mice after EMCV infection was significantly lower than that of TNF-alpha(+/+) mice (0% versus 67% on day 14). Injection of recombinant human TNF-alpha (0.2 to 4.0 microg/mouse IV) improved the survival of TNF-alpha(-/-) mice in a dose-dependent manner, indicating that TNF-alpha is essential for protection against viral myocarditis. The levels of viral titer and viral genomic RNA of EMCV in the myocardium were significantly higher in TNF-alpha(-/-) than in TNF-alpha(+/+) mice. Histopathological examination showed that the inflammatory changes of the myocardium were less marked in TNF-alpha(-/-) than in TNF-alpha(+/+) mice. Immunohistochemical analysis revealed that the levels of immunoreactivity of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in the myocardium were decreased in TNF-alpha(-/-) mice compared with TNF-alpha(+/+) mice.

CONCLUSIONS

These observations suggested that TNF-alpha is necessary for adhesion molecule expression and to recruit leukocytes to inflammatory sites, and thus, the lack of this cytokine resulted in failure of elimination of infectious agents. We concluded that TNF-alpha plays a protective role in the acute stage of viral myocarditis.

Oral clonidine premedication does not change efficacy of simulated epidural test dose in sevoflurane-anesthetized children

BACKGROUND

Caudal epidural anesthesia is often used as an adjunct to general anesthesia and for postoperative pain relief in children. In anesthetized children, epinephrine and isoproterenol are reliable indicators to detect accidental intravascular injection of a test dose. Oral clonidine, a useful premedicant in pediatric anesthesia, modifies hemodynamic responses to sympathomimetics, including catecholamines. The aim of the current study was to determine whether oral clonidine premedication alters the efficacy of a simulated intravascular test dose containing epinephrine or isoproterenol in sevoflurane-anesthetized children.

METHODS

One hundred twenty children (aged 1-7 yr) were randomly divided into six groups; control-saline, control-epinephrine, control-isoproterenol, clonidine-saline, clonidine-epinephrine, and clonidine-isoproterenol. The three clonidine groups received oral clonidine 4 microg/kg [DOSAGE ERROR CORRECTED] as premedication, whereas the three control groups did not receive any premedication. Anesthesia was maintained with sevoflurane at a level of 1.2 minimum alveolar concentration. After hemodynamics were stable, 0.1 ml/kg of 1% lidocaine containing epinephrine 0.5 mg/kg or isoproterenol 75 ng/kg was intravenously given to the two epinephrine or isoproterenol groups, respectively, to simulate intravascular injection of a test dose. The saline groups received saline alone instead of the test dose. Heart rate, blood pressure, and T-wave amplitude of electrocardiogram were recorded before and after administration of study drugs for subsequent analysis.

RESULTS

Test solution containing epinephrine increased heart rate, systolic blood pressure, and T-wave amplitude. Oral clonidine had no effect on elevation of these variables in response to epinephrine. The isoproterenol-containing test dose produced a prominent increase in heart rate and a less pronounced increase in systolic blood pressure and T-wave amplitude. Oral clonidine also failed to modify isoproterenol-induced hemodynamic and T-wave changes. Calculated sensitivity and specificity of epinephrine or isoproterenol were all 100% based on a new heart rate criterion (positive if >/= 10 beats/min) and were unaltered by oral clonidine premedication.

CONCLUSIONS

Epinephrine or isoproterenol is a reliable marker to detect accidental intravascular injection of a test dose with 100% sensitivity and specificity based on a new heart rate criterion in sevoflurane-anesthetized children. These data suggest that oral clonidine premedication does not alter the efficacy of a simulated epidural test dose containing epinephrine or isoproterenol.

Evaluation of two different homogeneous assays for LDL-cholesterol in lipoprotein-X-positive serum

BACKGROUND

The purpose of this study was to evaluate the performance of two homogeneous assays for LDL-cholesterol (LDL-C), a polyethylene/cyclodextrin (PC) assay and a detergent (D) assay, which are based on different principles, in cholestatic serum.

METHODS

We compared serum LDL-C concentrations determined by the two assays for healthy normolipidemic subjects (n = 42) and cholestatic patients (n = 51). LDL-C concentrations obtained with the homogeneous assays were also compared with those obtained by HPLC for patients' sera. In the interference study, conjugated bile acids were added to normal serum, and their effects on the two assays were examined. The effects of lipoprotein-X (LP-X), intermediate-density lipoprotein (IDL), and apolipoprotein (apo) E-rich HDL on the LDL-C assays were also investigated by adding these lipoproteins to normal serum.

RESULTS

The LDL-C concentrations obtained with the D assay were higher than those obtained with the PC assay in the serum with high LP-X. The bias for LDL-C vs LP-X in cholestatic serum correlated with LP-X concentration (r = 0.582; P: <0.0001; n = 51). In the interference study, no effect of bile acids on the LDL-C assays was observed. However, the D assay measured 51.0% of the cholesterol in LP-X, whereas no reactivity was observed for LP-X in the PC assay. In addition, the D assay and the PC assay measured IDL-cholesterol at 31.2% and 52.4%, respectively, and measured apo E-rich HDL-C at 7.6% and 17.8%, respectively.

CONCLUSIONS

Although both homogeneous LDL-C assays are suitable for most cases, the present study showed that each homogeneous assay has a different limitation for cholestatic serum with gross alterations in lipoproteins.

Lidocaine attenuates sepsis-induced diaphragmatic dysfunction in hamsters

OBJECTIVES

Sepsis or endotoxemia causes diaphragmatic dysfunction, which may contribute to respiratory distress. Toxic free radicals are partly responsible for the pathogenesis. Lidocaine scavenges the reactive molecules. The purpose of the current study was to examine whether lidocaine prevents the diaphragmatic dysfunction of sepsis.

DESIGN

Prospective, randomized animal study.

SETTING

University research laboratory.

SUBJECTS

A total of 40 male Golden-Syrian hamsters.

INTERVENTIONS

The animals were randomly allocated to one of five groups (n = 8 each): hamsters undergoing sham laparotomy alone and receiving saline infusion (Sham group), those undergoing cecal ligation with puncture (CLP) and receiving an infusion of saline (Sepsis group), those undergoing sham laparotomy and receiving infusion of lidocaine, 2 mg/kg/hr (Sham-LID group), those undergoing CLP and receiving infusion of lidocaine, 1 mg/kg/hr (Sepsis-LID 1 group), and those undergoing CLP and receiving infusion of lidocaine, 2 mg/kg/hr (Sepsis-LID 2 group). Subcutaneous infusion of saline or lidocaine was started 6 hrs before surgery and continued until 24 hrs after the operation when all hamsters were killed.

MEASUREMENTS AND MAIN RESULTS

Diaphragmatic contractility and fatigability were assessed in vitro by using muscle strips excised from the costal diaphragms. Diaphragmatic levels of malondialdehyde (MDA), an index of free radicals-mediated lipid peroxidation, were also measured. Twitch and tetanic tensions in the Sepsis group were reduced compared with the Sham group. Tensions generated during fatigue trials were decreased, and MDA levels were elevated in diaphragms from the Sepsis group. An infusion of 2 mg/kg/hr lidocaine attenuated contractile dysfunction, aggravation of fatigability, and the increase in MDA formation. In contrast, 1 mg/kg/hr lidocaine failed to do so. Electrophysiologic diaphragmatic characteristics in the Sham-LID group were similar to those in the Sham group.

CONCLUSIONS

Pretreatment with 2 mg/kg/hr but not 1 mg/kg/hr lidocaine attenuated sepsis-induced diaphragmatic dysfunction in hamsters assessed by contractile profiles and endurance capacity. This beneficial effect of lidocaine may be attributable, in part, to inhibition of lipid peroxidation in the diaphragm.

Hemodynamic abnormalities in the left atrial appendage in patients with paroxysmal atrial fibrillation, with special reference to albumin-contrast echocardiographic aspects

AIM

We assessed the prolonged dysfunction of the left atrial appendage caused by paroxysmal atrial fibrillation.

METHODS AND RESULTS

Transesophageal echocardiography with intravenous albumin-microspheres (Albunex, 0.2 ml/kg) was performed in 100 consecutive patients (44 patients in sinus rhythm without previous paroxysmal atrial fibrillation: 13 patients in sinus rhythm who had had previous episodes of paroxysmal atrial fibrillation; and 43 patients with sustained atrial fibrillation). We compared the left atrial appendage ejection fraction and degree of opacification in the left atrial appendage with Albunex in the groups. Patients with previous paroxysmal atrial fibrillation had lower left atrial appendage ejection fractions than patients in sinus rhythm without paroxysmal atrial fibrillation (33 +/- 14 vs. 47 +/- 14%, p < 0.001). More than half of the patients (7/13 [54%]) with previous paroxysmal atrial fibrillation showed delayed and incomplete opacification of the left atrial appendage with Albunex.

CONCLUSION

We conclude that paroxysmal atrial fibrillation causes left atrial appendage stunning, at least in some patients.

Attenuation of hyperoxia-induced diaphragmatic dysfunction with lidocaine in hamsters

OBJECTIVE

Toxic free radicals cause dysfunction of respiratory muscles, probably leading to respiratory distress. Exposure to high concentrations of oxygen generates plenty of free radicals. Lidocaine scavenges the reactive molecules. The purposes of the current study were first to examine whether hyperoxia impairs diaphragmatic function, and second, to assess the effects of lidocaine on hyperoxia-induced diaphragmatic dysfunction, if developed.

DESIGN

Prospective, randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Forty and 48 adult male Golden-Syrian hamsters (110-150 g) in parts I and II studies, respectively.

INTERVENTION

In the part I study, hyperoxia for 5 and 6 days reduced diaphragmatic contractility and enhanced fatigue. In the part II study, hamsters were randomly allocated to one of six groups (n = 8 each): exposure to air for 6 days with saline (group A-S) or lidocaine infusion (group A-L), exposure to 100% oxygen for 5 days with saline (group 05-S) or lidocaine (group 05-L), and exposure to 100% oxygen for 6 days with saline (group 06-S) or lidocaine (group 06-L). Saline or lidocaine (2 mg/kg/hr) was subcutaneously given immediately before exposure to air or oxygen. Diaphragmatic contractility and fatigability were assessed in vitro using muscle strips excised from the costal diaphragms. Diaphragmatic levels of malondialdehyde (MDA), an index of free radical-mediated lipid peroxidation, were measured. These variables were compared between groups.

MEASUREMENTS AND MAIN RESULTS

Twitch and tetanic tensions in groups 05-S and 06-S were reduced compared with group A-S. Tensions generated during fatigue trials were also decreased in groups 05-S and 06-S. MDA levels were elevated in diaphragms from these groups. In groups 05-L and 06-L, contractile dysfunction, deterioration of fatigability, and MDA formation in the diaphragm were attenuated.

CONCLUSIONS

Lidocaine attenuated hyperoxia-induced diaphragmatic dysfunction assessed by contractile profiles and fatigability in hamsters. This beneficial effect may be attributable, in part, to inhibition of lipid peroxidation.

[Anesthetic management of a patient with mitochondrial encephalomyopathy]

A 46-year-old female with mitochondrial encephalomyopathy underwent the replacement of right femur head under continuous epidural anesthesia. Considering that this disease is a neuromuscular disorder, general anesthesia should be avoided. In addition, the patients with mitochondrial encephalomyopathy tend to show increased concentrations of lactate and pyruvate caused by perioperative stress. Use of lactated Ringer's solution may elevate these concentrations. We managed this patient uneventfully with continuous epidural anesthesia and the use of acetated Ringer's solution during the perioperative period. We consider that continuous epidural anesthesia is useful for a patient with mitochondrial encephalomyopathy.

L-tryptophan-kynurenine pathway metabolite 3-hydroxyanthranilic acid induces apoptosis in macrophage-derived cells under pathophysiological conditions

Accumulation of L-kynurenine and 3-hydroxyanthranilic acid (3HAA) occurs in the monocyte-derived cells following immune stimulation, and may derive from L-tryptophan following induction of indoleamine-2,3-dioxygenase. In the present study, we evaluate the possibility that 3HAA acts as an endogenous inducer of monocyte/macrophage apoptosis. Supplementation with 200 microM of 3HAA, but not other L-tryptophan metabolites tested, significantly increased the number of apoptotic cells in both THP-1 and U937 cells. Catalase, superoxide dismutase and manganese ions markedly enhanced apoptosis in the presence of 3HAA in these cells. The present results suggest that 3HAA induces the macrophage/monocyte apoptosis under certain conditions, which may be relevant to pathophysiology of inflammatory conditions.

The effect of phosphodiesterase III inhibitors on human neutrophil function

OBJECTIVES

Neutrophils play an important role in ridding the body of bacteria and cellular debris. Several neutrophil functions are thought to be regulated by inotropes that increase cellular levels of cyclic adenosine monophosphate, including phosphodiesterase (PDE) inhibitors. We have investigated the effect of amrinone, milrinone, and olprinone, type III PDE (PDE-III) inhibitors, on several human neutrophil functions.

DESIGN

Prospective in vitro study.

SETTING

Academic research laboratory.

SUBJECTS

Neutrophils isolated from 12 healthy adult volunteers.

INTERVENTIONS

We measured chemotaxis, phagocytosis, reactive oxygen species production, intracellular calcium ion concentration, and cyclic adenosine monophosphate levels in neutrophils in the absence and the presence (at clinically relevant concentrations, 10 times, and 100 times those concentrations) of amrinone, milrinone, or olprinone. We also measured reactive oxygen species production under the same condition in a xanthine-xanthine oxidase system

MEASUREMENTS AND MAIN RESULTS

None of the PDE-III inhibitors impaired neutrophil chemotaxis or phagocytosis. Amrinone at clinically relevant or higher concentrations and milrinone at high concentrations reduced superoxide, hydrogen peroxide, and hydroxyl radical levels in neutrophils and in the xanthine-xanthine oxidase system. Olprinone did not have those effects, and none of the PDE-III inhibitors had an effect on intracellular calcium ion concentration or cyclic adenosine monophosphate production in neutrophils stimulated by a chemotactic factor.

CONCLUSIONS

The ability of amrinone to scavenge reactive oxygen species at clinically relevant concentrations while not affecting neutrophil function suggests that the PDE inhibitor can be used without detriment in severely ill patients.

A comparison of rabeprazole, lansoprazole, and ranitidine for improving preoperative gastric fluid property in adults undergoing elective surgery

Acid aspiration syndrome at the induction of anesthesia is still a potentially life-threatening complication. Its severity is affected by both pH and volume of the gastric juice that is aspirated. We compared the effects of rabeprazole (a new proton pump inhibitor), lansoprazole, and ranitidine on gastric fluid properties in a prospective, randomized, double-blinded fashion in 180 adult patients undergoing elective surgery. Patients were divided into six groups (n = 30 in each) according to their premedication. Patients in each group received placebo-rabeprazole (PLA-RAB), rabeprazole-placebo (RAB-PLA), rabeprazole-rabeprazole (RAB-RAB), lansoprazole-lansoprazole (LAN-LAN), placebo-ranitidine (PLA-RAN), or placebo-placebo (PLA-PLA) for the first-second medication. Each dose of the study drug was 20 mg for rabeprazole, 30 mg for lansoprazole, and 150 mg for ranitidine. The first medication was given orally at 9:00 PM on the day before surgery and the second at 5:30 AM on the day of surgery. Each patient fasted overnight and took the drug with 20 mL of water. After tracheal intubation, gastric fluid was aspirated via an orogastric tube, and the volume and pH of the aspirate was measured. Preoperative gastric fluid acidity and volume were improved by the study drugs in the following order: PLA-RAN (pH 5.3, volume 0.10 mL/kg), RAB-RAB, LAN-LAN, PLA-RAB, and RAB-PLA (pH 3.8, volume 0.22 mL/kg). The proportion of patients at risk of acid aspiration syndrome according to the traditional criteria (pH < 2.5 and volume > 0.4 mL/kg) was minimized in Groups RAB-RAB and PLA-RAN (0%). We concluded that a single morning dose of ranitidine rather than two doses (bedtime and morning) of rabeprazole was the most effective premedicant to control gastric fluid properties and to minimize the risk of aspiration pneumonitis.

IMPLICATIONS

Acid aspiration syndrome at the induction of anesthesia is rare but still a potentially life-threatening complication. We compared rabeprazole, lansoprazole, and ranitidine for reduction of preoperative gastric fluid acidity and volume in elective surgery and found that a combination of bedtime and morning doses of rabeprazole, or a morning dose of ranitidine, similarly minimized the variables. In adult patients who are at risk of aspirating gastric contents, improvement of gastric fluid environment by rabeprazole can reasonably be anticipated to provide protection against pneumonitis should regurgitation and aspiration of gastric contents occur.

The effects of sarpogrelate on superoxide production by human neutrophils

BACKGROUND AND OBJECTIVES

Superoxide anion (O2-) released from neutrophils plays an important role in antibacterial host defense system and tissue auto-injury. Sarpogrelate, a serotonin-receptor antagonist, has been successfully used for management of chronic pain caused by arterial occlusive or ischemic vascular diseases, or by microcirculation disturbances. Suppression of O2- generation may be detrimental to infection or contribute to the therapeutic approach to these diseases, the pathogenesis of which probably includes neutrophil activation. No data regarding the effects of sarpogrelate on neutrophil functions are available despite the possible clinical concern. The purpose of this study was to determine whether sarpogrelate reduces O2- production by human neutrophils using an in vitro system. In addition, we examined changes in concentrations of the intracellular calcium ion ([Ca2+]i), which is responsible for one of the mechanisms of the neutrophils' O2- production.

METHODS

The O2- production by human neutrophils or the xanthine-xanthine oxidase system and [Ca2+]i were measured in the absence and the presence (at clinically relevant concentrations: 0.1x, 10x, and 100x these concentrations) of sarpogrelate.

RESULTS

Sarpogrelate inhibited O2- production of neutrophils in a dose-dependent manner. The drug at a clinically relevant concentration suppressed this neutrophil function. In contrast, sarpogrelate failed to inhibit O2-generation by the cell-free (xanthine-xanthine oxidase) system. Elevation of [Ca2+]i in neutrophils stimulated by a chemotactic factor was dose-dependently attenuated with sarpogrelate.

CONCLUSIONS

These findings suggest that sarpogrelate (even at clinically relevant concentrations) is able to inhibit O2- production by neutrophils. However, the drug failed to quench an excessive amount of O2- (similar to the level produced by neutrophils). There is a possibility that the inhibitory effect of the drug on [Ca2+]i response in neutrophils may contribute to impairment of the neutrophils' O2- production. Further studies using in vivo systems are required to elucidate the inhibitory effects of sarpogrelate on O2- in clinical settings.