Fungal-derived cues promote ocular autoimmunity through a Dectin-2/Card9-mediated mechanism

Uveitis (intraocular inflammation) is a leading cause of loss of vision. Although its aetiology is largely speculative, it is thought to arise from complex genetic-environmental interactions that break immune tolerance to generate eye-specific autoreactive T cells. Experimental autoimmune uveitis (EAU), induced by immunization with the ocular antigen, interphotoreceptor retinoid binding protein (IRBP), in combination with mycobacteria-containing complete Freund's adjuvant (CFA), has many clinical and histopathological features of human posterior uveitis. Studies in EAU have focused on defining pathogenic CD4⁺ T cell effector responses, such as those of T helper type 17 (Th17) cells, but the innate receptor pathways precipitating development of autoreactive, eye-specific T cells remain poorly defined. In this study, we found that fungal-derived antigens possess autoimmune uveitis-promoting function akin to CFA in conventional EAU. The capacity of commensal fungi such as Candida albicans or Saccharomyces cerevisae to promote IRBP-triggered EAU was mediated by Card9. Because Card9 is an essential signalling molecule of a subgroup of C-type lectin receptors (CLRs) important in host defence, we evaluated further the proximal Card9-activating CLRs. Using single receptor-deficient mice we identified Dectin-2, but not Mincle or Dectin-1, as a predominant mediator of fungal-promoted uveitis. Conversely, Dectin-2 activation by α-mannan reproduced the uveitic phenotype of EAU sufficiently, in a process mediated by the Card9-coupled signalling axis and interleukin (IL)-17 production. Taken together, this report relates the potential of the Dectin-2/Card9-coupled pathway in ocular autoimmunity. Not only does it contribute to understanding of how innate immune receptors orchestrate T cell-mediated autoimmunity, it also reveals a previously unappreciated ability of fungal-derived signals to promote autoimmunity.

Prophage-mediated defence against viral attack and viral counter-defence

Temperate phages are common, and prophages are abundant residents of sequenced bacterial genomes. Mycobacteriophages are viruses that infect mycobacterial hosts including Mycobacterium tuberculosis and Mycobacterium smegmatis, encompass substantial genetic diversity and are commonly temperate. Characterization of ten Cluster N temperate mycobacteriophages revealed at least five distinct prophage-expressed viral defence systems that interfere with the infection of lytic and temperate phages that are either closely related (homotypic defence) or unrelated (heterotypic defence) to the prophage. Target specificity is unpredictable, ranging from a single target phage to one-third of those tested. The defence systems include a single-subunit restriction system, a heterotypic exclusion system and a predicted (p)ppGpp synthetase, which blocks lytic phage growth, promotes bacterial survival and enables efficient lysogeny. The predicted (p)ppGpp synthetase coded by the Phrann prophage defends against phage Tweety infection, but Tweety codes for a tetrapeptide repeat protein, gp54, which acts as a highly effective counter-defence system. Prophage-mediated viral defence offers an efficient mechanism for bacterial success in host-virus dynamics, and counter-defence promotes phage co-evolution.

Terminal ileum duplication: an unusual case of small bowel obstruction

Duplications of the alimentary tract are uncommon congenital anomalies that usually present during infancy and early childhood. The case of an adolescent presenting with small bowel obstruction secondary to a duplication cyst is presented and the challenges in the management described.

Fast pitch softball injuries

The popularity of fast pitch softball in the US and throughout the world is well documented. Along with this popularity, there has been a concomitant increase in the number of injuries. Nearly 52% of cases qualify as major disabling injuries requiring 3 weeks or more of treatment and 2% require surgery. Interestingly, 75% of injuries occur during away games and approximately 31% of traumas occur during nonpositional and conditioning drills. Injuries range from contusions and tendinitis to ligamentous disorders and fractures. Although head and neck traumas account for 4 to 12% of cases, upper extremity traumas account for 23 to 47% of all injuries and up to 19% of cases involve the knee. Approximately 34 to 42% of injuries occur when the athlete collides with another individual or object. Other factors involved include the quality of playing surface, athlete's age and experience level, and the excessive physical demands associated with the sport. Nearly 24% of injuries involve base running and are due to poor judgement, sliding technique, current stationary base design, unorthodox joint and extremity position during ground impact and catching of cleats. The increasing prevalence of overtraining syndrome among athletes has been attributed to an unclear definition of an optimal training zone, poor communication between player and coach, and the limited ability of bone and connective tissue to quickly respond to match the demands of the sport. This has led routinely to arm, shoulder and lumbar instability, chronic nonsteroidal anti-inflammatory drug (NSAID) use and time loss injuries in 45% of pitching staff during a single season. Specific attention to a safer playing environment, coaching and player education, and sport-specific training and conditioning would reduce the risk, rate and severity of fast pitch traumas. Padding of walls, backstops, rails and dugout areas, as well as minimising use of indoor facilities, is suggested to decrease the number of collision injuries. Coaches should be cognisant of overtraining, vary day-to-day training routines to decrease repetitive musculoskeletal stress, focus on motor skills with equal emphasis on speed and efficiency of movement, and use drills that reinforce sport-specific, decision making processes to minimise mental mistakes. Conditioning programs that emphasise a combination of power, acceleration, flexibility, technical skill, functional capacity and injury prevention are recommended. Due to the limited body of knowledge presently available on this sport, a greater focus on injury surveillance would provide a clearer picture of injury causation and effective management procedures, leading toward safer participation and successful player development.

Fiberoptic bronchoscopic placement of self-expandable metallic airway stents for the treatment of tracheobronchial obstruction and fistulas

Tracheobronchial stent use has been reported in the medical literature for more than 40 years. Silicone stents are the most widely used stents in therapy for varying tracheobronchial lesions at most centers. However, newer designs and modifications of stents are now available with delivery systems that have been designed to facilitate using fiberoptic bronchoscopy. We describe our initial experience placing 13 self-expandable metallic Wallstent stents, including the covered design, in a total of seven patients via a fiberoptic bronchoscope. All patients had benign or malignant obstructing lesions and one patient had an associated malignant tracheoesophageal fistula. The procedure was technically easy and was well tolerated. Following stenting there was a visible increase in airway diameter and a marked improvement in symptoms for all patients. Median survival after stent placement is currently 10 months.

Improved results in the management of surgical candidates with lung cancer

BACKGROUND

Perioperative mortality and morbidity after lung resection for carcinoma are generally reported to be 3% to 6% and 15% to 30%, respectively, and higher in the elderly and those with limited cardiopulmonary reserve.

METHODS

To minimize this risk and extend the surgical option to more high-risk patients, we adopted a protocol in 1991 that included preoperative digitalis, subcutaneous heparin and venoocclusive stockings, aggressive perioperative pulmonary toilet, and video-directed limited resections for many patients with limited pulmonary reserve. In October 1996, we reviewed our results with 173 consecutive patients (median age, 60 years; range, 17 to 89 years) undergoing operation for suspected lung carcinoma. Forty-one patients were 70 years old or older, and 70 patients were considered high risk on the basis of advanced age (> or = 70 years), poor cardiac or pulmonary reserve, or serious medical comorbidity. Procedures included pneumonectomy (n = 31), lobectomy (n = 83), bilobectomy (n = 12), and limited resection (n = 45). Two patients had unresectable disease.

RESULTS

Hospital mortality was 1.6% (3/173) and morbidity was experienced by 15% (26/173). Among the high-risk subgroup mortality was 4.2% (3/70) and morbidity was 20% (14/70; p < 0.03). For the older patients these values were 4.8% (2/41) and 17.9% (7/41), respectively.

CONCLUSIONS

Morbidity and mortality from lung resections may be minimized with the perioperative management strategy outlined above. This would allow more high-risk patients to benefit from surgical resection, and do so with an acceptably low risk.

Anecdotal episodes on Surgical Eye Expeditions (S.E.E.)

1. It is important to share your skills with international colleagues. 2. S.E.E. International offers participants global opportunities and challenges. 3. You can enrich your personal and professional life by helping blind patients to see.

Compound A concentrations during sevoflurane anesthesia in children

BACKGROUND

Sevoflurane is a new inhalation agent that should be useful for pediatric anesthesia. Sevoflurane undergoes degradation in the presence of carbon dioxide absorbents; however, quantification of the major degradation product (compound A) has not been evaluated during pediatric anesthesia. This study evaluates sevoflurane degradation compound concentrations during sevoflurane anesthesia using a 2-1 fresh gas flow and a circle system with carbon dioxide absorber in children with normal renal and hepatic function.

METHODS

The concentrations of compound A were evaluated during sevoflurane anesthesia in children using fresh soda lime as the carbon dioxide absorbent. Nineteen patients aged 3 months-7 yr were anesthetized with sevoflurane (2.8% mean end-tidal concentration) using a total fresh gas flow of 21 in a circle absorption system. Inspiratory and expiratory limb circuit gas samples were obtained at hourly intervals, and the samples were analyzed using a gas chromatography-flame ionization detection technique. Carbon dioxide absorbent temperatures were measured in the soda lime during anesthesia for hepatic and renal function studies. Venous blood samples were obtained before anesthesia, at the end of anesthesia, and 2h after anesthesia for plasma inorganic fluoride ion concentration.

RESULTS

The maximum inspiratory concentration of compound A was 5.4 +/- 4.4 ppm (mean +/- SD), and the corresponding expiratory concentration was 3.7 +/- 2.7 ppm (mean +/- SD). The maximum inspiratory compound A concentration in any patient was 15 ppm. Mean concentrations of compound A peaked at intubation and remained stable, declining slightly after 120 min of anesthesia. The duration of anesthesia was 240 +/- 139 min (mean +/-SD). Maximum soda lime temperature ranged between 23.1 degrees C and 40.9 degrees C. There was a positive correlation between maximum absorbent temperature and maximum compound A concentration (r2 = 0.58), as well as between the child's body surface area and maximum compound A concentration (r2 = 0.59). Peak plasma inorganic fluoride ion concentration was 21.5 +/- 6.1 microgmol/1. There were no clinically significant changes in hepatic or renal function studies performed 24 h postanesthesia.

CONCLUSIONS

Sevoflurane anesthesia of 4 h in normal children using a 2-1 flow circle system produced concentrations of compound A of 15 ppm or less. There was no evidence of abnormality of renal or hepatic function up to 24 h after anesthesia; however, larger studies will be required to confirm the absence of organ toxicity.

Searching for the Magic Johnson effect: AIDS, adolescents, and celebrity disclosure

The objectives of this study were to measure changes in AIDS-related attitudes and behaviors in adolescents in the 13 months following Magic Johnson's disclosure that he was HIV positive, and to test whether gender, race, age, sexual experience, and pre-existing HIV-avoidant behaviors would emerge as significant dependent variables. Adolescent clinic attendees (N = 181) ages 12-19 in four cities completed a questionnaire assessing change in AIDS-related attitudes and behaviors since Johnson's announcement. Respondents were divided into low-risk and at-risk groups. Sixty percent of respondents reported that Magic Johnson's announcement had increased their awareness of AIDS, 65.4% reported increased self-efficacy in a sexual situation, 37.2% reported that they had changed their perceived AIDS risk, 37.8% described increased resistance to peer pressure for sexual intercourse. The low-risk group was more likely to report increased self-efficacy and resistance to peer pressure but no change in perceived risk or increased AIDS awareness. Significant relationships were found between gender and increased AIDS awareness, gender and increased resistance to peer pressure to engage in sexual intercourse, race and increased AIDS awareness, and more lifetime sex partners and increased self-efficacy.

Understanding mechanical ventilation: patient monitoring, complications, and weaning

Mechanical ventilation can provide life saving support to critically ill patients with respiratory failure. The implementation of appropriate monitoring techniques and an awareness of potential complications can increase the safety of mechanical ventilation. Several efficacious weaning methods can be utilized and none is clearly superior to the others. The improper use of any weaning technique can result in respiratory muscle fatigue delaying extubation. Determining patient suitability for extubation is an inexact science. The physical examination during a spontaneous breathing trial and the use of the rapid shallow breathing index can assist the clinician in the difficult decision as to the timing of extubation.

Understanding mechanical ventilation: indications for and initiation of therapy

The growing complexity of mechanical ventilators and the proliferation of new ventilator modes may confuse and intimidate clinicians who on occasion must manage a mechanical ventilator. The fundamental indications for and types of mechanical ventilation are reviewed, and guidelines for basic ventilator settings are provided. By understanding and applying these essentials, the clinician can provide effective mechanical ventilation to most patients who require it. A subsequent article published in this journal will review the related topics of patient monitoring during mechanical ventilation, complications of mechanical ventilation, and weaning from mechanical ventilation.

Guidelines for overseas eye surgery expeditions using short-term volunteers. Surgical Eye Expeditions international

Many developing countries face the overwhelming problem of addressing preventable and curable blindness. United States-based ophthalmologists can make important contributions in this regard by volunteering to teach and deliver eye care overseas. However, there are a number of potential risks and difficulties. Surgical Eye Expeditions (SEE) International has developed a logistical outline and planning checklist designed to minimize or avoid such problems. Critical components include a firm timetable, advanced planning, advance contact with a local ophthalmologist or organization, and a thorough understanding of the importance of adapting to the needs of other cultures. With a little planning, the average philanthropic ophthalmologist can make major contributions to individuals and communities in developing nations.

Sevoflurane degradation product concentrations with soda lime during prolonged anesthesia

STUDY OBJECTIVES

To evaluate the decomposition of sevoflurane in soda lime during prolonged sevoflurane anesthesia in humans. To evaluate for evidence of renal or hepatotoxicity as a result of exposure to these sevoflurane degradation compounds.

DESIGN

Prospective evaluation in healthy volunteers.

SETTING

Clinical research unit and postanesthesia care unit of a university hospital.

PATIENTS

Six healthy male volunteers.

INTERVENTIONS

Subjects were anesthetized with sevoflurane 1 to 1.2 minimum alveolar concentration for greater than 9 hours with a semiclosed circuit anesthetic technique (5-liter total flow) with fresh soda lime as the absorbent.

MEASUREMENTS AND MAIN RESULTS

Laboratory tests of renal and hepatic function were performed before anesthesia and 1 and 5 days after anesthesia. During sevoflurane anesthesia, inhalation and exhalation circuit limb gas samples were obtained for degradation compound analysis. Only one degradation product, fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (compound A), was detected. Inhalation concentration was maximal (7.6 +/- 1.0 ppm) at 2 hours and did not increase further after this time point. There were no differences in preanesthesia and postanesthesia tests of hepatic and renal function.

CONCLUSIONS

Levels of the degradation compound (compound A) produced in semiclosed circuit sevoflurane anesthesia with soda lime are well below potential toxic levels and thus appear safe. When sevoflurane is administered under these conditions for prolonged anesthesia, concentrations of compound A do not continue to increase throughout anesthesia.

Renal concentrating function with prolonged sevoflurane or enflurane anesthesia in volunteers

BACKGROUND

Sevoflurane, a new inhalational anesthetic, is biotransformed, producing peak plasma inorganic fluoride concentrations that may exceed 50 microM. We evaluated plasma inorganic fluoride concentrations with prolonged (> 9 MAC-h) sevoflurane or enflurane anesthesia in volunteers and compared renal concentrating function with desmopressin testing 1 and 5 days after anesthesia.

METHODS

Fourteen healthy male volunteers received either enflurane or sevoflurane (1-1.2 MAC) for more than 9 MAC-h. Each volunteer was administered three tests of renal concentrating function, with intranasal desmopressin and urine collections performed 1 week before anesthesia and 1 and 5 days after anesthesia. Venous blood samples were obtained for plasma fluoride concentrations during and after anesthesia. Creatinine clearance was determined by 24-h urine collections 7 days before and 4 days after anesthesia. Urine samples were obtained before and 1, 2, and 5 days after anesthesia for determination of n-acetyl-beta-glucosaminidase and creatinine concentrations.

RESULTS

Prolonged sevoflurane anesthesia (9.5 MAC-h) did not impair renal concentrating function on day 1 or 5 postanesthesia, as determined by desmopressin testing. Maximal urinary osmolality on day 1 postanesthesia was decreased (< 800 mOsm/kg) in two of seven enflurane-anesthetized volunteers; however, mean results did not differ from the those of the sevoflurane group. Mean peak plasma fluoride ion concentrations were 23 +/- 1 microM 6 h postanesthesia for enflurane and 47 +/- 3 microM at the end of anesthesia for sevoflurane (P < 0.01). There were no changes in creatinine clearance or urinary n-acetyl-beta-glucosaminidase concentration in either anesthetic group.

DISCUSSION

Prolonged sevoflurane anesthesia did not impair renal concentrating function, as evaluated with desmopressin testing 1 and 5 days postanesthesia in healthy volunteers. Although with prolonged enflurane anesthesia, mean maximal osmolality values on day 1 postanesthesia did not differ from sevoflurane values, there was evidence in two volunteers at this time point of impairment in renal concentrating function, which normalized 5 days postanesthesia. These results occurred despite a higher peak plasma fluoride ion concentration and greater total inorganic fluoride renal exposure with sevoflurane anesthesia.

Renal function after sevoflurane or enflurane anesthesia in the Fischer 344 rat

Sevoflurane is metabolized to inorganic fluoride, a potential nephrotoxin. To evaluate the nephrotoxic potential of sevoflurane, 1-yr-old male Fischer 344 rats were anesthetized with 10 minimal alveolar anesthetic concentration (MAC) h sevoflurane or enflurane with or without pretreatment with biotransformation-enhancing agents. Peak serum fluoride levels reached 35 microM with sevoflurane anesthesia after pretreatment with phenobarbital and 40 microM after enflurane anesthesia after pretreatment with isoniazid. One day after anesthesia, sevoflurane-anesthetized rats concentrated urine normally in response to subcutaneous administration of 1-deamino-8-D-arginine vasopressin and exhibited no increase in urinary excretion of N-acetyl beta-glucosaminidase. Isoniazid-treated, enflurane anesthetized rats developed a 31% reduction in maximal urinary concentrating ability and a 3.5-fold increase in excretion of N-acetyl-beta-glucosaminidase. Sevoflurane produced no evidence of fluoride-induced nephrotoxicity in noninduced or enzyme-induced rats. Under similar conditions, enflurane produced laboratory evidence of nephrotoxicity.

Plasma inorganic fluoride levels with sevoflurane anesthesia in morbidly obese and nonobese patients

Administration of several of the inhaled anesthetics result in plasma inorganic fluoride concentrations that are higher in obese compared to nonobese patients. Sevoflurane, a new inhaled anesthetic, is metabolized to inorganic fluoride; however, plasma inorganic fluoride levels with sevoflurane anesthesia in obese subjects have not been evaluated. We studied plasma inorganic fluoride concentrations during and after sevoflurane surgical anesthesia in morbidly obese (n = 13, body mass index > 35) and nonobese (n = 10) patients. Sevoflurane anesthesia in 60% nitrous oxide/40% oxygen was administered with a semiclosed circle absorption system. Mean anesthetic duration was 1.4 minimum alveolar anesthetic concentration (MAC) hours (sevoflurane MAC = 2.05%) for both groups. Pre- and postoperative blood urea nitrogen, creatinine, and liver function tests were evaluated. Venous blood samples were obtained during and after anesthesia for plasma inorganic fluoride analysis. In six morbidly obese and nonobese patients arterial blood samples were obtained during and after sevoflurane anesthesia for determining sevoflurane blood concentration. Plasma fluoride concentrations during and after anesthesia did not differ between morbidly obese and non-obese groups. Peak plasma inorganic fluoride ion concentrations were 30 +/- 2 mumol/L (mean +/- SEM) in obese and 28 +/- 2 mumol/L in nonobese patients 1 h after discontinuing anesthesia. The hourly rate of change of fluoride ion concentration in plasma during anesthesia was similar between the groups. The maximal recorded plasma fluoride concentrations were 49 mumol/L in an obese patient and 42 mumol/L in a nonobese patient. Pre- and postoperative hepatic and renal tests did not differ significantly in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Interphenylene 7-oxabicyclo[2.2.1]heptane oxazoles. Highly potent, selective, and long-acting thromboxane A2 receptor antagonists

A series of interphenylene 7-oxabicyclo[2.2.1]heptane oxazoles (2) were prepared and evaluated for their thromboxane (TxA2) antagonistic activity in vitro and duration of action in vivo. Examination of the carboxyl side chain indicated that the interphenylene ring substitution pattern and, to a lesser extent, chain length were important factors in determining TxA2 antagonistic potency. For the carboxyl side chain, ortho substitution, a single methylene spacer between the interphenylene and oxabicycloheptane rings, and a propionic acid side-chain length were determined to be optimal. With respect to the oxazole side chain a wide range of amide substituents with diverse structures and lipophilicities were compatible with potent antagonistic activity. Finally, an acidic functional group on the alpha-chain and a hydrogen bond acceptor on the 4-position of the oxazole ring were critical for potent activity. From the analogs prepared 42 (BMS-180,291: [(+)-1S-(1 alpha, 2 alpha, 3 alpha, 4 alpha)-2-[[3-[4-[(n- pentylamino)carbonyl]-2-oxazolyl]-7-oxabicyclo[2.2.1]hept-2- yl]methyl]benzenepropanoic acid) was found to be a potent, selective, and orally-active TxA2 antagonist with a long duration of action and has been selected as a candidate for clinical development. In human platelet-rich plasma, 42 inhibited arachidonic acid (800 microM) and U-46,-619 (10 microM) induced aggregation with I50 values of 7 and 21 nM, respectively. Radioligand binding studies of 42 with [3H]-SQ 29,548 showed a Kd value of 4.0 +/- 1.0 nM in human platelet membranes. Both in vitro and in vivo studies indicated 42 was devoid of direct agonistic activity. In vivo 42 (0.2 mg/kg, po) showed extended protection (T50 = 14.4 h) from U-46,619 (2 mg/kg, iv) induced death in mice, and a single oral dose of 42 (3 mg/kg) abolished U46,619-induced platelet aggregation ex vivo in African green monkeys for > 24 h.

Quantification of the degradation products of sevoflurane in two CO2 absorbants during low-flow anesthesia in surgical patients

Sevoflurane, a new inhalational anesthetic agent has been shown to produce degradation products upon interaction with CO2 absorbants. Quantification of these sevoflurane degradation products during low-flow or closed circuit anesthesia in patients has not been well evaluated. The production of sevoflurane degradation products was evaluated using a low-flow anesthetic technique in patients receiving sevoflurane anesthesia in excess of 3 h. Sevoflurane anesthesia was administered to 16 patients using a circle absorption system with O2 flow of 500 ml/min and average N2O flow of 273 ml/min. Preoperative and postoperative hepatic and renal function studies were performed. Gas samples were obtained from the inhalation and exhalation limbs of the anesthetic circuit for degradation product analysis and analyzed by gas chromatography/mass spectrometry for four degradation products. The first eight patients received sevoflurane anesthesia using soda lime, and the following eight patients received anesthesia using baralyme as the CO2 absorbant. CO2 absorbant temperatures were measured during anesthesia. Of the degradation products analyzed, only one compound [fluoromethyl-2, 2-difluoro-1-(trifluoromethyl) vinyl ether], designated compound A, was detectable. Concentrations of compound A increased during the first 4 h of anesthesia with soda lime and baralyme and declined between 4 and 5 h when baralyme was used. Mean maximum inhalation concentration of compound A using baralyme was 20.28 +/- 8.6 ppm (mean +/- SEM) compared to 8.16 +/- 2.67 ppm obtained with soda lime, a difference that did not reach statistical significance. A single patient achieved a maximal concentration of 60.78 ppm during low-flow anesthesia with baralyme. Exhalation concentrations of compound A were less than inhalation concentrations, suggesting patient uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary epithelial cell urokinase-type plasminogen activator. Induction by interleukin-1 beta and tumor necrosis factor-alpha

Diffuse alveolar damage, presenting clinically as adult respiratory distress syndrome, is characterized initially by widespread intra-alveolar fibrin deposition. Alveolar epithelial cells play a central role in the subsequent repair process. We have recently shown that alveolar epithelial cells have the capacity to promote fibrinolysis (Marshall, B. C., Sageser, D. S., Rao, N. V., Emi, M., and Hoidal, J. R. (1990) J. Biol. Chem. 265, 8198-8204) and may therefore directly participate in the extensive remodeling that follows acute lung injury. Because the tissue repair process occurs in an acute inflammatory setting, we investigated the effects of inflammatory mediators on urokinase-type plasminogen activator (u-PA) expression by pulmonary epithelial cells. We found that interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) upregulated PA activity in A549 human pulmonary epithelial cells. Biosynthetic labeling and immunoprecipitation showed that both cytokines caused marked accumulation of newly synthesized u-PA. Northern blot analyses demonstrated that both IL-1 beta and TNF-alpha induced relatively rapid accumulation of u-PA mRNA which did not require de novo protein synthesis and was substantially inhibited by glucocorticoids. Nuclear run-off transcription studies showed that both cytokines caused rapid transcriptional activation of the u-PA gene. While the effects of IL-1 beta and TNF-alpha were qualitatively similar, some differences emerged. Most notably, TNF-alpha led to a more sustained accumulation of u-PA mRNA than did IL-1 beta. In contrast to their effects on u-PA expression, IL-1 beta and TNF-alpha had minimal effect on PA inhibitor-1 expression. These effects of IL-1 beta and TNF-alpha, mediators known to play a key role in acute lung injury and inflammation, may promote lysis of alveolar fibrin by alveolar epithelium, thereby aiding in restoration of normal lung architecture.

Plasma inorganic fluoride with sevoflurane anesthesia: correlation with indices of hepatic and renal function

The biotransformation and plasma inorganic fluoride ion production of sevoflurane (the new volatile anesthetic) during and after surgical anesthesia was studied in 50 ASA I or II surgical patients. Twenty-five additional patients served as controls by receiving isoflurane. Sevoflurane or isoflurane was administered with a semiclosed (total gas flow, 2 L/min O2) circle absorption system for durations of 1.0 to greater than 7.0 minimal alveolar concentration (MAC) hours for surgical anesthesia (sevoflurane MAC, 2.05%; isoflurane MAC, 1.15%). Preoperative and postoperative blood urea nitrogen and creatinine concentrations were determined. Blood samples were obtained during and after anesthesia in both groups for determining anesthetic blood concentration analysis and plasma fluoride level. Plasma fluoride concentrations did not significantly increase during isoflurane anesthesia. Sevoflurane biotransformation produced a mean peak plasma inorganic fluoride concentration of 29.3 +/- 1.8 mumol/L, 2 h after anesthesia, which decreased to 18 mumol/L concentration by 8 h after anesthesia. The peak plasma inorganic fluoride ion concentration correlated with duration of sevoflurane anesthetic exposure. Five patients given sevoflurane had peak levels transiently exceeding 50 mumol/L, and one of these had a history of ingesting drugs potentially producing hepatic enzyme induction. No increases in postoperative levels of creatinine, blood urea nitrogen, direct bilirubin, or hepatic transaminase and no changes in serum electrolyte level occurred in either anesthetic group. Indirect bilirubin concentration increased significantly after sevoflurane anesthesia, but the increase was not of clinical significance (from 0.30 +/- 0.03 to 0.38 +/- 0.06 mg/dL). Indirect bilirubin concentrations did not increase after isoflurane anesthesia; the concentrations reached 0.31 +/- 0.04 mg/dL and did not differ significantly from those found with sevoflurane.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical comparison of sevoflurane and isoflurane in healthy patients

We compared blood pressure and heart rate changes in healthy patients during anesthesia with sevoflurane (n = 50) versus isoflurane (n = 25) and the rate of recovery after such anesthesia. After premedication with intravenous administration of midazolam, induction of anesthesia with thiopental, and intubation of the trachea facilitated with succinylcholine or vecuronium, anesthesia was maintained with approximately 1 MAC (sevoflurane, 2.05%; isoflurane, 1.15%) of the volatile anesthetic in oxygen for the duration of the operation. Anesthetic concentration was varied as indicated to maintain arterial blood pressure at +/- 20% of baseline values. Sevoflurane and isoflurane produced similar systolic and diastolic arterial blood pressures, but heart rate after incision was faster in patients given isoflurane. Recovery of response to command was shorter in patients given sevoflurane than that in patients given isoflurane (7.5 +/- 0.5 min versus 18.6 +/- 2.0 min). Consistent with this finding, venous blood drawn after anesthesia showed a more rapid initial decay with sevoflurane. Nausea and vomiting were comparable in both groups. We conclude that sevoflurane anesthesia, as compared with isoflurane, is associated with possible advantageous effects on heart rate and recovery.

Coaches. A missing link in the health care system

The number of children and adolescents who participate in interscholastic athletics demands attention to the quality of the coaching they receive and to the opportunities that the athlete-coach relationship provides for modification of high-risk behaviors, social skills training, and character formation. Although the need for coaches has increased due to the advent of girls' athletic programs, which was mandated by Title IX legislation, only a minority of states require certification for coaches who work in school systems. Four coaching curricula are summarized and contrasted: the American Coaching Effectiveness Program, the curriculum of the National Youth Sports Coaches Association, the Athletic Health Care System, and the Coach Effectiveness Training Program. Recommendations for coach certification by states, physician advocacy for coaching standards, and improved sports medicine services are discussed.

The effects of sevoflurane, halothane, enflurane, and isoflurane on hepatic blood flow and oxygenation in chronically instrumented greyhound dogs

Inhalational anesthetics produce differential effects on hepatic blood flow and oxygenation that may impact hepatocellular function and drug clearance. In this investigation, the effects of sevoflurane on hepatic blood flow and oxygenation were compared with those of enflurane, halothane, and isoflurane in ten chronically instrumented greyhound dogs. Each dog randomly received enflurane, halothane, isoflurane, and sevoflurane, each at 1.0, 1.5, and 2.0 MAC concentrations. Mean arterial blood pressure and cardiac output decreased in a dose-dependent fashion during all four anesthetics studied. Heart rate increased compared to control during enflurane, isoflurane, and sevoflurane anesthesia and did not change during halothane anesthesia. Hepatic arterial blood flow and portal venous blood flow were measured by chronically implanted electromagnetic flow probes. Hepatic O2 delivery and consumption were calculated after hepatic arterial, portal venous, and hepatic venous blood gas analysis. Hepatic arterial blood flow was maintained with sevoflurane and isoflurane. Halothane and enflurane reduced hepatic arterial blood flow during all anesthetic levels compared to control (P less than 0.05), with marked reductions occurring with 1.5 and 2.0 MAC halothane concomitant with an increase in hepatic arterial vascular resistance. Portal venous blood flow was reduced with isoflurane and sevoflurane at 1.5 and 2.0 MAC. A somewhat greater reduction in portal venous blood flow occurred during 2.0 MAC sevoflurane (P less than 0.05 compared to control and 1.0 MAC values for sevoflurane). Enflurane reduced portal venous blood flow at 1.0, 1.5, and 2.0 MAC compared to control. Halothane produced the greatest reduction in portal venous blood flow (P less than 0.05 compared to sevoflurane).(ABSTRACT TRUNCATED AT 250 WORDS)

Interphenylene 7-oxabicyclo[2.2.1]heptane thromboxane A2 antagonists. Semicarbazone omega-chains

A series of chiral interphenylene 7-oxabicyclo[2.2.1]heptane semicarbazones 19-26 were prepared and evaluated for their in vitro thromboxane (TxA2) antagonistic activity and in vivo duration of action. The potency of 19-26 was found to highly dependent on the substitution pattern of the interphenylene ring and decreased in the order ortho greater than meta much greater than para. SQ 35,091 (25), [1S-(1 alpha,2 alpha,3 alpha,4 alpha)]-2-[[3-[[[(phenylamino) carbonyl]hydrazono]methyl]-7-oxabicyclo[2.2.1]hept-2-yl]methyl] benzenepropanoic acid, was identified as a potent and long-acting TxA2 antagonist. In human platelet rich plasma SQ 35,091 inhibited arachidonic acid (800 microM) and U-46,619 (10 microM) induced aggregation with I50 values of 3 and 12 nM, respectively. In contrast, no inhibition of ADP (20 microM) induced aggregation was observed at greater than 1000 microM. Receptor binding studies with [3H]-SQ 29,548 showed SQ 35,091 was a competitive antagonist with a Kd value of 1.0 +/- 0.1 nM in human platelet membranes. In vivo SQ 35,091 (0.2 mg/kg po) showed extended protection (T50 = 16 h) from U-46,619 (2 mg/kg iv) induced death in mice. These compounds have for the first time demonstrated that a metabolically stable interphenylene alpha-sidechain can be introduced into a prostanoid-like series of TxA2 antagonists with the maintainance of potent antagonistic activity.

Contributions of liver perfusion flow rate and enzyme inhibition to altered verapamil clearance with halothane: a study in the isolated perfused rat liver

Verapamil clearance is reduced during halothane administration. This study evaluated relative contributions of reduced hepatic flow rate and hepatic metabolizing enzyme inhibition by halothane as a cause of reduced verapamil clearance. An isolated perfused rat liver model was utilized in which flow rate could be fixed during halothane administration. Perfusions were performed on five to six livers under each of the following conditions: (a) control--40 mL/min flow rate with no anesthetic exposure; (b) 1.5% halothane--40 mL/min; (c) 2.25% halothane--40 mL/min; (d) reduced flow--20 mL/min with no anesthetic exposure; and (e) reduced flow with 1.5% halothane--20 mL/min. Halothane caused dose-dependent decreases in both total hepatic and intrinsic clearance rates (P less than 0.05). With no anesthetic exposure, a flow reduction of 50% (20 mL/min) also gave a large reduction (P less than 0.05) in hepatic clearance of verapamil compared with the control condition (40 mL/min). The addition of 1.5% halothane to the reduced flow condition was not associated with further reduction in hepatic clearance rate. Results of this study suggest that although both reduced hepatic perfusion and hepatic enzymatic inhibition by halothane administration are associated with decreased verapamil clearance, a greater proportion of this decrease appears to be due to reductions in hepatic flow. The present results may apply to other drugs used in anesthesia that have high hepatic extraction ratios; thus, clearance of these drugs may be more dependent on hepatic blood flow than on hepatic enzyme activity.

Serum ammonia levels in response to glycine infusion in normal and cirrhotic rats

Elevated serum ammonia may play a role in central nervous system derangement after transurethral resection of the prostate. Glycine used as a surgical irrigant for prostate resection produces ammonia as a by-product after liver and renal metabolism. The presence of liver dysfunction often leads to an inability to remove generated ammonia from the circulation. To determine whether the presence of cirrhosis allows significant metabolism of glycine and the resulting serum ammonia levels generated, the production of ammonia after glycine infusion was examined in normal and cirrhotic rats. Hepatic microsomal enzyme induction was produced in male Sprague-Dawley rats given sodium phenobarbital, added to the drinking water to hasten the development of cirrhosis, by increasing the toxicity of carbon tetrachloride given intragastrically to one group at weekly intervals for production of cirrhosis. A control group was maintained under similar conditions except for carbon tetrachloride dosing. The end point for production of cirrhosis was the development of ascites. Two weeks after the development of ascites in the cirrhotic rats and the discontinuation of phenobarbital in both groups, both control and cirrhotic rats were anesthetized with IP pentobarbital and glycine (1.25 g/kg; 7.5%) was given intravenously. Venous blood samples were taken at intervals up to 120 min for serum ammonia analysis. After the final serum ammonia sample, lethal pentobarbital injection was given and livers and kidneys removed for histologic analysis. Terminal body weight, glycine dose, and renal histology were not different between groups. Liver weights were greater in cirrhotic rats. Baseline serum ammonia levels were also greater int he cirrhotic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatotoxicity and inhalation anesthetics: views in the era of isoflurane

The halogenated inhalation anesthetics continue to be an important group of drugs in current anesthesia practice. The purpose of this article is to discuss current concepts of the mechanisms of halothane-induced hepatotoxicity and to attempt to answer the question: Do all halogenated inhalation anesthetics share halothane's propensity to hepatotoxicity?

Chronology of halothane-induced antigen expression in halothane-exposed rabbits

Multiple halothane exposures in rabbits generate modified liver proteins or antigens that appear to incorporate the metabolic intermediate of halothane, trifluoroacetyl halide (TFA), as identified by specific anti-TFA antibody. These halothane-induced antigens are most prevalent throughout the second to fourth days following a single halothane exposure and are in highest concentration after the second and third exposure. In addition, five consecutive halothane exposures at 2-week intervals caused the sustained expression of these halothane-induced antigens throughout the first 4 days following the last exposure. By the seventh day, however, antigen expression began to decline. Although there is great heterogeneity in the molecular weights of the halothane-induced antigens, the predominant proteins appear to be 85k, 58k, 53k, 37k and 24k. These liver proteins could reflect self proteins altered by trifluoroacetylation by halothane metabolites and may be potential immunogens in the initiation of a halothane-induced immune response.

Halothane hepatotoxicity in guinea pigs

A recently reported animal model of halothane-associated hepatotoxicity in males of a colored strain of guinea pig was further characterized as to possible sex and strain specificity in outbred albino Amana, inbred albino Hartley, inbred colored strain 2, and inbred colored strain 13 guinea pigs. Exposure to 1% halothane for 4 hr in 21% O2 proved to be hepatotoxic in both sexes. Forty-eight hours after halothane exposure fatty vacuolization of hepatocytes was present in all animals. Histologically identifiable hepatic necrosis occurred in 60% of the guinea pigs exposed, along with concomitant increases in SGPT. Approximately one half of these responding animals had extensive centrilobular necrosis, which was still present 96 hr after halothane exposure. Females of the inbred strain 2 and males and females of strain 13 were the most susceptible to halothane-induced hepatic necrosis whereas the inbred Hartley strain was almost totally refractory to necrosis. Outbred Amana and male inbred strain 2 animals exhibited an intermediate hepatotoxic response. Comparison of the halothane-associated hepatic lesion with that induced by anoxic/ischemic mechanisms, (exposure to low (8%) oxygen during 1.7% enflurane anesthesia) showed obvious differences in the morphology of the hepatic necrosis and the apparent time course of lesion development. This guinea pig model of halothane-associated hepatotoxicity appears to be superior to previous animal models in that no pretreatment of the guinea pigs is required, both sexes are affected, and the resulting hepatic lesion is more persistent.

Clinical pharmacokinetics of the inhalational anaesthetics

At present, the most widely used inhalational anaesthetics are the halogenated, inflammable vapours halothane, enflurane, isoflurane and the gas nitrous oxide. The anaesthetic effect of these agents is related to their tension or partial pressure in the brain, represented at equilibrium by the alveolar concentration. The minimum alveolar concentration for a specific agent is remarkably constant between individuals. The uptake and distribution of inhalational anaesthetics depends on inhaled concentration, pulmonary ventilation, solubility in blood, cardiac output and tissue uptake. Inhalational anaesthetics are mainly eliminated by pulmonary exhalation, but significant amounts of halothane are removed by hepatic metabolism. Inhalational agents currently in use have acceptable pharmacokinetic characteristics, and clinical acceptance depends on their potential for adverse effects. Induction of anaesthesia with halothane is rapid and relatively pleasant and it is the agent of choice for paediatric anaesthesia. Between 20 and 50% is metabolised, and the parent drug is a potent inhibitor of drug metabolism. Post-operatively enzyme induction may follow. The major disadvantages of halothane are myocardial depression, propensity to evoke cardiac arrhythmias and the rare but serious halothane hepatitis. Induction and recovery from enflurane anaesthesia is rapid. Metabolism accounts for 5 to 9% of the elimination. The metabolic product inorganic fluoride may in rare cases cause renal toxicity. Enflurane is a weak inhibitor of drug metabolism at anaesthetic concentrations. Enflurane depresses circulation more than halothane by reducing both myocardial contractility and systemic vascular resistance, but cardiac rhythm is stable. Enflurane anaesthesia may, unlike the other agents, induce epileptic activity. Enflurane is widely used as replacement for halothane in adults. Despite its low blood-gas solubility, the airway irritability of isoflurane precludes a faster induction of anaesthesia than with halothane. Isoflurane is almost resistant to biodegradation. Myocardial contractility is maintained during isoflurane anaesthesia and cardiac rhythm is stable except for the occurrence of tachycardia in some patients. Isoflurane is the inhalational agent of choice for neurosurgical operations. Sevoflurane is an experimental ether vapour: induction and recovery is fast and pleasant. It is metabolised to the same extent as enflurane and subnephrotoxic concentrations of inorganic fluoride may result. Sevoflurane has fewer respiratory and cardiovascular depressant effects than halothane and may be a future alternative for paediatric anaesthesia.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of a halothane-induced humoral immune response in rabbits

An animal model of halothane-induced liver injury has been developed in the rabbit to study the production of humoral immunity towards a biotransformation intermediate of halothane. Rabbits exposed many times to halothane in a 75% O2/25% N2 atmosphere produce an antibody that cross-reacts with the trifluoroacetyl moiety of trifluoroacetylated rabbit serum albumin (TFA-RSA). The generation of this halothane-induced immunogen is dependent upon high oxygen tension as shown by the minimal anti-TFA antibody response seen in rabbits exposed to halothane in a 14% O2/86% N2 atmosphere. In addition, halothane exposure of rabbits specifically immunized with the metabolite-carrier complex, TFA-RSA, induces a secondary antibody response toward the immunogen. In rabbits, either immunized with TFA-RSA or not, multiple halothane exposures induce populations of antibodies with varying specificities. Evidence suggests that predominance of the metabolic intermediate, the ensuing immunogen, and the subsequent antibody response depends upon the oxygen tension during successive exposures to halothane. These successive exposures could potentially generate many different immunogens resulting in varied antibody specificities.

Adverse effects of volatile anaesthetics

The volatile inhalation anaesthetics have been implicated in a variety of adverse viscerotoxic reactions. In general, they have been proven to produce very few non-predicted toxicities. Hepatitis caused by halothane now seems to be the only major problem in this regard with these drugs in current practice. The evidence is convincing that this reaction is based initially on biotransformation. Thus decreases in the amount of biotransformation and lessened production of reactive metabolic products would theoretically produce a safer anaesthetic. While not perfect in all circumstances, enflurane and isoflurane come close to achieving the goal of decreased adverse viscerotoxic events.

Oxygen concentrations required for reductive defluorination of halothane by rat hepatic microsomes

The free oxygen concentrations required for reductive defluorination of halothane by rat hepatic microsomes from control and phenobarbital- (PB) and polychlorinated biphenyl-(PCB) treated animals were determined. Halothane-exposed microsomes from treated rats generated measurable levels of fluoride ion after 30 min incubations with oxygen concentrations of 5% or less. Microsomes from control animals produced fluoride only if the free oxygen concentration was 2% or less. During anoxic (0% oxygen) incubations, defluorination rates of 2.10 +/- 0.17, 5.55 +/- 0.38, and 5.46 +/- 0.30 nmol fluoride X mg protein-1 X 30 min-1 were observed for microsomes from control, PB, and PCB rats, respectively. Normalizing the maximal rates of defluorination to the microsomal cytochrome P-450 content yielded values of 5.14 +/- 1.40, 3.70 +/- 0.15, and 2.38 +/- 0.26 nmol fluoride X nmol cytochrome P-450-1 X 30 min-1 for control, PB, and PCB microsomes, respectively. Oxygen concentrations required for reductive metabolism of halothane by isolated rat hepatic microsomes are close to normal physiologic free oxygen concentrations of 4-5% reported for centrilobular areas of the rat liver. Thus even slight reductions in hepatic oxygenation during anesthetic exposure could lead to enhanced reductive biotransformation, an observation found in rat models of halothane-associated hepatic injury. The large differences among the treatment groups in the rates of fluoride ion generated per nanomole cytochrome P-450 indicate that enzyme induction regimens disproportionately increase those isozymes of hepatic cytochrome P-450 that are not involved with the reductive defluorination of halothane.

Comparison of the requirements for hepatic injury with halothane and enflurane in rats

A rat model of enflurane-associated hepatotoxicity was compared with the halothane-hypoxia (HH) model (adult male rats, phenobarbital induction, 1% halothane, 14% O2, for 2 hr). The enflurane-hypoxia heating (EHH) model involved exposing phenobarbital-pretreated male adult rats to 1.5-1.8% enflurane at 10% O2 for 2 hr with external heating to help maintain body temperature. Exposure to either anesthetic without temperature support led to a decrease in body temperature of 7-9 degrees C, while heating the animals during anesthesia resulted in only a 0.5-2 degree decrease. Reducing the oxygen tension to 10% O2 combined with heating the animals during exposure produced significant decreases in the oxidative metabolism of both halothane and enflurane as compared to exposures of 14% O2. The same conditions also caused a significant increase in the reductive metabolism of halothane, indicating that a severe hepatic hypoxia or anoxia occurs during anesthesia at 10% O2 with external heating. The time course of lesion development in the HH model paralleled results obtained with an oral dose of CCl4: gradual progression of necrosis up to 24 hr. EHH resulted in a classic hypoxic/anoxic injury with elevated serum glutamate pyruvate transaminase values and a watery vacuolization of centrilobular hepatocytes immediately after exposure. The HH model required phenobarbital pretreatment of the rats for expression of hepatic injury; EHH did not. Heating of the animals during anesthesia exposure was necessary for enflurane-induced hepatoxicity but had little effect on the HH model. Exposure to 5% O2 without anesthetic mimicked EHH in both requirements for and type of hepatic injury.

The involvement of endotoxin in halothane-associated liver injury

Since endotoxin, lipopolysaccharides (LPS), have been implicated as a causative factor in the development of hepatic necrosis in rats exposed to hepatotoxic levels of several chemical agents, the role of LPS in the halothane-hypoxia (HH) model of hepatic damage in male Sprague-Dawley rats was investigated. When injected intravenously immediately after halothane anesthesia, a subnecrotic dose of LPS (0.5 mg/kg; Escherichia coli 026:B6) was found to markedly potentiate HH-induced hepatic necrosis. Pretreatment of the animals with the antiendotoxin agent, lactulose, prior to exposure to halothane reduced the hepatic damage normally seen from HH. A possible mechanism of LPS-induced potentiation was indicated by changes in hepatic calcium levels at 24 h after treatment. Endogenous LPS may play a role in HH-induced hepatic necrosis, and the mechanism of LPS-induced potentiation may be due to an LPS-related membrane dysfunction.

Cognitive and psychosocial differences between I and E locus of control aged persons

An abbreviated version of Rotter's Locus of Control (LOC) Scale was administered to 437 elderly subjects living in a variety of settings in an urban community. The group (n = 199) which scored below the median (internal orientation) was compared with the group (n = 238) which scored at or above the median (external orientation) on an array of 37 cognitive and psychosocial variables. Significant differences, mostly favoring the internal subjects, were found on 13 of the variables, suggesting relatively better self-reported health status, cognitive, and personal-social functioning on their part. These results are in general agreement with most other reports dealing with the relationships between LOC responses of the aged and their psychosocial functioning. Step-wise multiple regression analysis of the intercorrelations among the 37 variables and LOC show only seven are significant and these account for no more than 13 percent of the variance. The overall impression is that LOC has a reliable relationship to limited aspects of cognitive and psychosocial functioning, but that the power of its predictive effectiveness is still quite limited.