[Clinical study on meropenem in pediatric field].

We studied clinical effects of meropenem (MEPM, SM-7338), a newly developed parenteral carbapenem beta-lactam drug, and following results were obtained. The patients were administered with 16-20 mg/kg of MEPM every 8 hours using 1 hour drip infusion. 1. Clinical effects of MEPM were studied in 10 children with various infectious diseases: 1 with acute bronchitis, and 2 each with acute tonsillitis, acute bronchopneumonia, acute pneumonia, acute urinary infection, and 1 with pertussis pneumonia. The case of pertussis pneumonia later developed bronchiolitis obliterans, hence a steroid and gamma-globulin were used. This case was excluded from the clinical evaluation. The efficacy rate was 100% (9/9), and the bacteriological eradication rate was 100% (6/6). 2. No side effects were noted. Clinical laboratory test values were investigated in 10 patients. There was a case of abnormal laboratory test findings with mild elevations of liver functions such as GOT, GPT, and gamma-GTP. These abnormalities disappeared in 1 week after the end of therapy.


[Pharmacokinetic and clinical studies on meropenem].

Pharmacokinetic and clinical studies on meropenem (MEPM, SM-7338), a new developed carbapenem, were performed and the following results were obtained. 1. Absorption/excretion: Pharmacokinetics of MEPM was studied in 9 children using doses of 10 mg/kg and 20 mg/kg by a 30 minute-drip infusion. Peak plasma levels and plasma half-lives of the 2 doses were 28.4 and 43.0 micrograms/ml, and 0.70 and 0.80 hours, respectively. Their urinary recovery rates were 42.5 to 67.6% and 29.9 to 62.6%, respectively. Cerebrospinal fluid levels and penetration rates of MEPM in a patient with purulent meningitis were 0.66 to 4.01 micrograms/ml and 1.6 to 12.2%, respectively. 2. Clinical study: Forty-nine patients were treated with MEPM at doses exceeding 100 mg/kg/day with purulent meningitis and 30 to 60 mg/kg/day with other infections. MEPM gave "excellent" or "good" responses in 48 cases, an efficacy rate of 98.0%. Only one patient with subdural abscess showed fair response. Diarrhea and rash were observed in 1 case each. Abnormal laboratory test results were noted in 5 patients including elevation of GOT, GPT and eosinophils. In no cases the treatment had to be discontinued.


[Clinical evaluation of a new carbapenem, meropenem, in infants and children].

A new carbapenem antibiotic, meropenem (MEPM), was evaluated for its safety and efficacy in 33 infants and children. MEPM was effective in all the 32 evaluable cases including 4 cases of bacterial meningitis and 5 cases of Pseudomonas aeruginosa infections. The mean half life of plasma concentrations of MEPM was 0.84 +/- 0.09 hours after 30 minutes intravenous drip infusion. Mild diarrhea (2 cases), transient elevation of transaminases (8 cases), and transient eosinophilia (2 cases) were associated with the MEPM therapy, but none of them was problematic. These data suggest that MEPM is safe in infants and children and could be one of the therapeutic agents for severe infections or infections in compromised hosts.


[Laboratory and clinical studies on meropenem in pediatrics].

Laboratory and clinical studies on meropenem (MEPM), a new carbapenem antibiotic, were carried out in the field of pediatrics. The results obtained are summarized below. 1. The antibacterial activities of MEPM against clinically isolated organisms in our department were generally high. 2. After 30 minutes intravenous drip infusion of MEPM at a dose of 20 mg/kg to 2 children, the mean peak plasma level of MEPM was 32.7 micrograms/ml at the end of infusion with a mean half-life of 1.45 hours. The mean cumulative urinary recovery rate in the first 6 hours after infusion was 43.6%. 3. Fifteen patients with various bacterial infections were treated with MEPM. The clinical efficacy rate was 100% and the bacteriological efficacy rate was 95.2%. 4. No side effects were observed except in 1 case of mild diarrhea. Some abnormal laboratory test results were obtained, but they were mild with slight elevations of GOT and GPT in 2 cases.


[Clinical studies of meropenem in pediatric field].

We have carried out clinical studies on meropenem (MEPM, SM-7338), the results are summarized as follows. Treatment with MEPM was made in 13 cases of pediatric bacterial infections including 9 cases of pneumonia and 2 cases of colitis and 1 case each of purulent tonsillitis, and pharyngitis. Results obtained were excellent in 10 cases, good in 3 cases. No significant side effects due to the drug were observed in any cases, except in 1 case each of eosinophilia, elevated gamma-GTP, elevated total bilirubin and elevated GPT.


[Studies on meropenem in the field of pediatrics].

The pharmacokinetics and the clinical effectiveness of meropenem (MEPM) were examined in the field of pediatrics. The results are summarized as follows. 1. A 4-year-6-month-old girl with suppurative meningitis (Haemophilus influenzae) was treated by intravenous drip infusion of MEPM in a daily dose of 29 mg/kg which was divided into 4 dosages, each dosage being infused over 30 minutes, and the drug concentration in cerebrospinal fluid was determined. Upon completion of infusion on the 2nd day of treatment, the drug concentration was 2.52 micrograms/ml, which corresponded to 3.6% of the drug concentration in the blood. 2. MEPM was used in 10 patients, including 3 with suppurative lymphnoditis, 2 with staphylococcal scalded skin syndrome (SSSS) and 1 each with pneumonia, suppurative meningitis, suppurative knee arthritis, facial phlegmon and pyelonephritis. The daily doses ranged from 30 to 117.6 mg/kg, divided into 3 to 4 dosages and administered via intravenous drip infusion over 30 minutes. Clinical responses were evaluated as very good in 7 patients, good in 2 patients and fair in 1 patient, with an efficacy rate of 90%. 3. Isolated pathogens were 2 strains of Staphylococcus aureus, 1 strain of Klebsiella pneumoniae and 3 strains of Haemopilus influenzae. All of the 6 strains were eradicated, with an eradication rate of 100%. 4. In the safety evaluation, none of the patients was observed to have any side effects. Furthermore, no abnormal variations were found in laboratory test data possibly attributable to administration of MEPM.


[An improved tetrazolium agar medium for testing sugar fermentation in lactobacilli].

An improved tetrazolium agar medium for testing sugar fermentation in lactobacilli is described. Basal medium 86 was essentially a modified MRS broth with the omission of glucose. The standard formula was 30 micrograms/ml of 2,3,5-triphenyltetrazolium chloride, 2% sugar to be tested, and 2% agar in medium 86. Plates were incubated anaerobically for 2 days at 37C or 5 days at 30C, depending on the strain. With three strains each of group II and III lactobacilli, colorless, fermentation-positive colonies were clearly differentiated from red, fermentation-negative colonies. For three strains of group I lactobacilli, this medium was not satisfactory because they grew poorly on it unless supplemented with a sugar.


The occurrence of early sudden coronary artery occlusion following angioplasty may be predicted from the clinical characteristics of the patients and their coronary lesion morphology.

The aim of this study was to assess whether the incidence of early occlusion following angioplasty was greater among patients with unstable angina and whether the coronary lesions prone to early occlusion could be predicted from their angiographic appearance. Seventy-seven patients who had had a first angioplasty of a native vessel for stable or unstable angina in one twelve month period were included. The angiographic appearances of the angioplastied lesions were classified as either Type 1, which were smooth and unlikely to have thrombus or intimal rupture, or Type 2, which were irregular due to thrombus or intimal rupture. The lesion classification was compared to the patients' clinical features, i.e. stable or unstable angina, and the outcome of the angioplasty. Type 2 lesions occurred in 25% of patients with stable angina but 49% of patients with unstable angina (p less than 0.05). Early sudden occlusion of the angioplastied vessel occurred in 24% of patients with unstable angina but in only 3% of patients with stable angina (p less than 0.05) and in 6% of Type 1 lesions compared with 24% of Type 2 lesions (p less than 0.05). Thus it is possible to identify the clinical characteristics and angiographic appearances of those patients undergoing angioplasty who are most likely to experience early vessel occlusion.


Safety and efficacy of a modified catheter-mediated ablation of accessory pathways.

Fifty-one consecutive patients underwent modified catheter-mediated direct-current ablation of accessory pathways. Energy was delivered through the distal pair of electrodes (dual electrode configuration) of a 6F quadripolar catheter to the internal surface of the right or left atrioventricular (AV) annulus. In an attempt to prevent the later resumption of accessory pathway conduction, one additional shock was given after the initial successful interruption of accessory pathways. A mean of 2.7 shocks with cumulative energy of 453 +/- 32 Joules/patient interrupted the accessory pathways in 47 patients and modified the accessory pathway conduction in 2 patients. Forty-eight patients were asymptomatic and free of any antiarrhythmic agents with a follow-up ranging from 3-20 months (mean 12 +/- 1 months), without early or late serious complications (AV block or tamponade). Conduction characteristics, concealed or manifest, and recording of accessory pathway activity did not affect the outcome. Mean cumulative energy and number of applications of energy to achieve a successful outcome were lower in patients with concealed (376 +/- 31 Joules, 2.4 +/- 0.2 shocks) than manifest accessory pathways (516 +/- 50 Joules, 2.9 +/- 0.2 shocks). At the successful ablation sites, the mean shortest retrograde ventriculoatrial interval during orthodromic reentrant tachycardia (VA') was 80 +/- 3 msec (78% had VA' less than 90 msec) and was not different between concealed and manifest accessory pathways; the mean shortest antegrade AV interval was 47 +/- 3 msec in manifest preexcitation; the mean ratio of atrial to ventricular wave amplitude was not significantly different between left-sided (0.8 +/- 0.1) and right-sided (1.1 +/- 0.2) accessory pathways (p greater than 0.05). A successful outcome was achieved in 94% of 51 patients. This procedure is relatively safe and effective, regardless of the location of the accessory pathway.


Fixed subaortic stenosis in childhood. Medical and surgical course in 90 patients.

This study evaluated diagnostic criteria, clinical observations, surgical indications and complications in 90 cases of fixed subvalvular aortic stenosis. Echocardiography, catheter angiography and surgical findings indicated that 60 (66.6%) patients had subvalvular membranous stenosis, 20 (22.2%) patients had fibromuscular stenosis, 4 (4.4%) patients had membranous and fibromuscular stenosis, and 6 (6.6%) had a tunnel-type obstruction. Forty-two patients had additional cardiac anomalies, such as PDA, valvular aortic stenosis and VSD. Fifty patients were treated surgically. Thirty-six patients were evaluated by two-dimensional and Doppler echocardiography at post-surgical intervals ranging from 7 days to 11 years (mean 3.6 years). There were pathological echo findings in 12 patients. The prognosis of this anomaly depends upon early diagnosis and treatment. The results of this study support the importance of the two-dimensional and Doppler echocardiography in early diagnosis and follow-up of the surgical results in treatment of this anomaly.


Superiority of echocardiographically assisted blade atrial septostomy.

Blade atrial septostomy has been applied in 3 patients with transposition of the great arteries under two-dimensional echocardiography instead of fluoroscopy. The blade at the tip of the catheter was seen on an echo screen when it was in the left atrium. The blade was then extended and pulled slowly across the atrial septum from the left into the right atrium, under echocardiographic monitoring. The procedure was successful in all 3 patients. Interatrial communication measured echocardiographically was sufficient in size. Since the interatrial septum is clearly seen by means of echocardiography during blade atrial septostomy, the method is thought to be superior to fluoroscopy in the prevention of complications.


Peripartum cardiomyopathy.

Peripartum cardiomyopathy is a relatively rare complication of pregnancy, characterized by heart failure of obscure etiology during the antepartal or postpartal period. During a 10-year period in our hospital, of 36,882 women who delivered, 6 were diagnosed as having peripartum cardiomyopathy. The incidence in our hospital was estimated as 1:6,147 deliveries. Among these 6 patients, 2 cases with fulminating courses died 1 month after treatment. Two other cases had cardiomyopathy and multiple congestive heart failure and died after 3 years and 6 years. Only one case, whose cardiac size returned to normal within 4 months, completely recovered from this disease. Another survivor with persistent cardiomegaly was followed for 5 years and remained clinically stable. In addition to congestive heart failure, the occurrence of complications such as sepsis, hepatorenal failure, and arrhythmia were the major causes of death. According to the results of our study, return of cardiac chamber size to the normal range indicated a good prognosis. We concluded that the prognosis of peripartum cardiomyopathy depends upon the degree of cardiac dysfunction and the response to therapy.


Plasma t-PA/PAI-1 complex and blood coagulability in patients with coronary artery disease.

The t-PA/PAI-1 complex is a good indicator of the release of fibrinolysis activators and inhibitors from the vascular wall, but its clinical significance in chronic ischemic heart disease is unclear. The plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), and the t-PA/PAI-1 complex (including various coagulation factors) were assayed in 72 patients with coronary artery disease (CAD) and 29 control (C) subjects. The CAD patients were subdivided into 3 groups: single-vessel disease (G1, n = 30), double-vessel disease (G2, n = 20), and triple-vessel disease (G3, n = 22). The patients with triple-vessel disease had higher fibrinogen values (G3: 318 +/- 75 mg/dl, C: 263 +/- 56), factor VII activity (G3: 143 +/- 36%, C: 123 +/- 14), and t-PA antigen levels (G3: 4.7 +/- 0.8 ng/ml, C: 3.3 +/- 0.7) than controls. Patients with double- and triple-vessel disease also showed higher levels of factor VIII, vWF antigen, thrombin-antithrombin III complex (G1: 2.3 +/- 0.6 ng/ml, G2: 2.7 +/- 0.5, G3: 3.1 +/- 0.5, C: 2.0 +/- 0.5), and t-PA/PAI-1 complex (G1: 13.9 +/- 6.1 ng/ml, G2: 16.4 +/- 4.6, G3: 18.2 +/- 5.9, C: 10.7 +/- 4.9) than control subjects. The t-PA/PAI-1 complex levels were correlated significantly with the activities of factors VII and VIII and the thrombin-antithrombin III complex. These findings suggest that patients with CAD have greater blood coagulability than controls, and that this difference is related to the severity of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of clonidine on heart rate variability.

We compared the effects of intravenous infusions of clonidine and placebo on heart rate variability in 10 healthy male controls. Clonidine produced a significant decrease in blood pressure and significantly decreased the heart rate variability during quiet standing.


Antiarrhythmic action of naloxone. Suppression of picrotoxin-induced cardiac arrhythmias in the rat.

The antiarrhythmic properties of the opiate antagonist naloxone have been reported in a variety of models of arrhythmia. To determine the generality and the possible central involvement of its antiarrhythmic activity, the effects of naloxone were assessed against cardiac arrhythmias induced by intravenous bolus injections of picrotoxin. Naloxone at doses of 0.33 and 1 mg/kg significantly reduced the incidence and severity of picrotoxin-induced arrhythmias in a dose-related manner, without alteration of blood pressure and heart rate. The results demonstrate the antiarrhythmic efficacy of naloxone in an additional animal model. They further suggest that the antiarrhythmic actions of naloxone may be mediated by the central nervous system via both the autonomic and GABAergic pathways.


A case of right atrial mobile thrombus complicating multiple pulmonary emboli.

Right atrial thrombi are usually immobile. However, a mobile type mimicking a cardiac tumor, especially myxoma, has been described on rare occasions. We report here a case of atrial thrombus which was mobile in the cardiac chambers. A 29-year-old male was admitted because of exertional dyspnea. On admission, his echocardiogram showed an abnormal mass in the right atrium with a stalk attached to the interatrial septum. It decreased in size on the next day. On the fourth day of admission, it moved to the right ventricle. Multiple pulmonary emboli were revealed by the lung perfusion scintigram. Two days after the administration of intravenous urokinase, the abnormal mass in the cardiac chambers was no longer seen on the echocardiogram. This was a rare case of mobile atrial thrombus associated with multiple pulmonary emboli. Thrombolytic therapy appeared to be effective in this case.


Successful transseptal catheter electrical ablation of sustained ventricular tachycardia of possible intramuscular origin.

Low-energy electrical ablation at 100 joules was attempted via a catheter in a patient with sustained ventricular tachycardia (VT) refractory to drug therapy. The patient was a 17-year-old woman who had undergone complete surgical correction of a double outlet right ventricle at the age of 9. The first episode of VT appeared at the age of 17. It was refractory to procainamide and lidocaine and it was sustained until termination with direct countershock. Two different QRS morphologies of VT were documented in the electrophysiologic study and one was identical to the VT observed in the clinical course. Conventional drug therapy failed to prevent induction of VT and catheter electrical ablation was attempted. The earliest activation site during the clinical episode of VT was localized to the right ventricular side of the interventricular septum (site 14-15), but pacing from this site resulted in a slightly different QRS morphology from that of VT. At the left ventricular side of this site (site 2), pacing during VT resulted in a QRS morphology identical to that of VT but the electrogram of this site did not precede the onset of the surface QRS complex. From these findings, the origin of VT was considered to be in the muscular layer of the interventricular septum. The method of transseptal shock using two catheters was applied and direct countershock at 100 joules successfully ablated the VT.


Enhancing program implementation and maintenance through a multiphase approach to peer-based staff development.

School-based health education programs often are limited by failures in implementation and maintenance. While inservice training has proven beneficial, teacher training research indicates that the more complex the demands on teachers using innovative psychosocially based health education curricula, the greater the necessity for post-inservice follow-up staff development. Evidence is presented that 1) teachers respond to innovations in developmental stages, 2) a multiphase approach to staff development is necessary to assist teachers during each stage, 3) post-inservice staff development requires opportunities for teacher collaboration, 4) approaches to staff development should fit the stage of teacher development, and 5) the organizational context of staff development is critical. Peer-based approaches to post-inservice staff development are presented, with a review of strengths and limitations of each approach.


Adolescent health: a report to the U.S. Congress.

This article reports findings from an assessment by the Office of Technology Assessment (OTA), an analytical arm of the U.S. Congress. In brief, OTA found the conventional wisdom that American adolescents as a group are so healthy that they do not require health and related services is not justified. Even more disturbing, U.S. adolescents often face formidable barriers in trying to obtain health care. OTA suggested that Congress could act to 1) increase adolescents' access to health care, most effectively by supporting school- or community-based comprehensive health services specifically for adolescents, 2) restructure and reinvigorate the federal role in adolescent health, most visibly by creating an office of adolescent health in the U.S. Executive branch, and 3) improve adolescents' social environments, by providing more support to the families of adolescents, limiting adolescents' access to firearms, supporting the expansion of recreational opportunities for adolescents, and further supporting opportunities for community service. Congressional actions taken since the release of OTA's report are summarized.


Indicators of substance use among pregnant adolescents in the Mississippi Delta.

Data were collected from 293 pregnant adolescents living in the southern Illinois section of the Mississippi Delta region concerning their substance use behaviors in 1989 and 1990. Subjects used a variety of drugs in the past and present. For example, 24.4% of the sample reported they presently smoked cigarettes. Alcohol was used by 20.4% in the previous five months, while 5.2% reported marijuana use during the same period. Regression models designed to predict substance use produced adjusted r2 values of .30 (SE = 1.06) for cigarette use, .38 (SE = .49) for marijuana use, and .43 (SE = .59) for alcohol use. Significant indicators included peer and personal substance use behavior, parental substance use, and having previously received mental health treatment.


Nutrient contribution of the school lunch program: implications for healthy people 2000.

Cardiovascular disease-related nutrients were quantified in a school lunch program over a 15-year period. Methods included 24-hour dietary recall, menu weights, and recipe analysis. School lunch was eaten by 93% of students. School lunches provided 23% of daily kilocalories and 24%, 29%, and 20% of daily fat, protein, and carbohydrate intake, respectively, saturated fat and cholesterol from school lunch were 27% and 24% of daily total. School lunch provided 7% of daily sucrose and 32% of daily sodium. Children not eating school lunch had significantly greater polyunsaturated (p less than .001), carbohydrate (p less than .05), and sucrose (p less than .001) intakes. Though the school lunch contributed less than one-third of daily total nutrients, intakes of diet components related to cardiovascular disease risk were excessive. Sixty percent to 80% of children exceed daily total fat, saturated fat, cholesterol, and sodium intakes over recommended levels. Schools can influence childhood cardiovascular disease risk by providing students healthier foods, with education to promote positive lifestyles.


Adolescents' reasons for smoking.

Part of the Hutchinson Smoking Prevention Project, this study provides information on reasons reported by adolescents for their smoking behavior. A total of 1,615 10th grade students in 20 rural and suburban school districts in Washington state were asked why they currently smoke and why they first smoked. For beginning smoking, curiosity, social norms, and social pressure were the most frequently given reasons for smoking. For current smoking, pleasure and addiction were mentioned most often. A number of gender differences occurred with 10th grade students beginning and current smoking. More females than males reported social norms and social pressure as reasons for beginning to smoke, whereas for currently smoking, pleasure was given as a reason more frequently by females than males. When developing interventions, smoking prevention programs need to consider students' current and past smoking behavior, and the reasons they give for smoking.


An evaluation of sample preparation techniques for the GC/MS analysis of urinary mercapturic acid conjugates.

Recovery rates of four different techniques for the preparation of human urine samples spiked with N-acetyl-S-benzyl-L-cysteine (BMA) were compared at three different spiking levels. At concentrations of 1,000 ppm and 1 ppm in the urine, recoveries of BMA were greatest (80-96%) using an ion pair phase transfer technique and a C18 solid-phase extraction (C18) technique while an acidic ethyl acetate extraction method yielded 67-69% recoveries and a quaternary amine solid-phase extraction technique showed poor recoveries (5-7%). At 10 ppb, quantitative recovery could only be determined for the C18 technique due to interferences from samples prepared using the other three techniques. The results indicate that the C18 sample preparation technique followed by GC/MS analysis using stable isotopically labeled internal standards provides a rapid and accurate method for quantitation of mercapturic acids at low-ppb levels in the urine.


Collection and handling of clinical blood samples to assure the accurate measurement of cocaine concentration.

The measurement of serum cocaine concentration is difficult because it is rapidly metabolized in vivo and in vitro. Previous investigators have used sodium fluoride (0.5-3.0%) in an attempt to stabilize its concentration in samples of whole blood, but these concentrations of sodium fluoride are not readily available outside the analytical laboratory. This study was performed to assess the stability of cocaine in whole blood when stabilized in a commonly available concentration of sodium fluoride (0.25%), with or without concomitant refrigeration. Whole blood was enriched with cocaine to a final concentration of 900 ng/mL and added to flasks containing sodium fluoride (0, 0.25, 0.5, and 1.0%) or 0.25% sodium fluoride plus potassium oxalate (gray-top Vacutainer tubes), after which it was stored at 4 degrees C or at room temperature. Whole blood cocaine concentrations were measured at 0, 24, and 48 h by gas chromatography. Sodium fluoride at all concentrations, with or without refrigeration and potassium oxalate, effectively inhibited cocaine degradation, with 86-91% of the drug present after 48 h. In contrast, substantial degradation of cocaine occurred in the samples stored without sodium fluoride, regardless of temperature. Thus, the use of commercial gray-top Vacutainer tubes effectively stabilizes cocaine in blood during procurement, transport, and short-term storage.


Comparative kinetics of digoxin in serum and vitreous humor in a guinea pig model. II. Single oral dose administration.

In a continuation of work previously reported involving the comparative kinetics of digoxin in vitreous humor and serum after an intravenous dose, the present report describes the pharmacokinetics of digoxin in this model following the administration of a single oral dose. Serum and vitreous humor concentrations of digoxin were monitored by radioimmunoassay for 720 min after a single oral dose of 0.1 mg digoxin/kg. Serum concentrations peaked by 60 min and declined over the remaining observation period with a half-life of 360 min. Vitreous humor concentrations lagged behind the serum concentrations, peaked between 60 and 120 min, and then declined at a rate less than that of serum with convergence of concentration occurring in the 720-min samples. The vitreous humor-serum ratios ranged from a low of 0.003 (15 min) to a high of 0.98 at convergence. The impact of these findings upon forensic toxicologic practice is reviewed.


Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of bromisovalum.

A simple and rapid method for isolation of bromisovalum with Sep-Pak C18 cartridges from human whole blood, plasma, and urine containing allylisopropylacetylurea as an internal standard, is presented. Detection of the drugs was made by nonpolar wide-bore capillary gas chromatography (GC) with flame ionization. The drug-containing samples, after mixing with water, were directly applied to the cartridges and eluted with chloroform-methanol (9:1). The recoveries of bromisovalum with use of the cartridges were excellent. Bromisovalum and internal standard allylisopropylacetylurea could be satisfactorily separated from each other and from impurities with the wide-bore capillary column. The detection limit for bromisovalum was 2-5 ng in an injected volume.


The certification of cocaine and benzoylecgonine in a human urine standard reference material.

The concentrations of cocaine and benzoylecgonine (BE) in Standard Reference Material (SRM) 1508, cocaine and metabolites in freeze-dried human urine, were determined at the National Institute of Standards and Technology (NIST, formerly NBS) by two independent methods. For cocaine, one method was based on gas chromatography/mass spectrometry (GC/MS); the other was based on high-performance liquid chromatography (HPLC). For BE, one method was based on GC/MS; the other was based on flow injection analysis/thermospray mass spectrometry (FIA/MS). The results for each pair of methods were statistically evaluated. Concentrations were determined in the SRM for three levels of cocaine and three levels of benzoylecgonine. Methylecgonine, although present in the material, was not determined. For cocaine, the concentrations were 90, 263, and 429 ng/mL of human urine. For BE, the concentrations were 103, 259, and 510 ng/mL of human urine.


Diethyl ether interference with infrared breath analysis.

Diethyl ether vapor may substantially interfere with breath alcohol analysis by instruments based on infrared absorption at 9.5 microns. Exposure of two volunteers simultaneously to diethyl ether vapor for one hour followed immediately by breath tests on the Draeger Alcotest 7110, Siemens Alcomat V5.2F, and Seres Ethylometre 679T produced apparent alcohol readings in one subject of 0.4, 0.1, and 0.1 g/100 mL of blood respectively. Positive readings persisted in this subject for more than 3 hours. The second subject produced much lower readings of 0.03, 0.01, and 0.00, respectively. Readings persisted with the Alcotest 7110 for one hour. Gas chromatographic analyses of blood and breath samples confirmed that these readings were caused by diethyl ether and not ethanol. The blood concentration of diethyl ether in Subject A immediately after exposure was 25 mg/L. This level produced no clinically detectable neurological changes in the subject.


Determination of arsenic in fish by hydride generation atomic absorption spectrometry.

A method utilizing microwave dissolution in a closed Teflon bomb followed by hydride generation atomic absorption spectrometry has been used for the routine analysis of arsenic in fish species from the coast of the province of Granada, Spain. The technique was evaluated for decomposing biological standard reference material (BCR mussel tissue) for arsenic analyses. The precision of the results ranged from 2.78 to 6.99%. The recovery percentages ranged from 96.33 to 100.00%. The values determined in the samples indicated slight contamination by this element in the zone. The concentrations of arsenic in fish ranged from 0.396 to 45.716 micrograms/g.


Screening for drugs of abuse with the Roche ONTRAK assays.

A family of manual, qualitative, latex agglutination inhibition immunoassay screening tests (ONTRAK, Roche) for amphetamines, barbiturates, cocaine, marijuana, morphine, and phencyclidine were evaluated. The assays are inexpensive, rapid, portable, and easy to perform, requiring little training to obtain proficiency. The tests are sensitive to drug concentrations at or around the stated cutoff values. The ONTRAK results agree well with the results obtained from fluorescence polarization immunoassay (FPIA) or radioimmunoassay (RIA) screening and GC/MS confirmation. Potential drawbacks of the test kits include the subjective nature of the qualitative assays and the lack of a positive control. The ONTRAK system provides a reasonable means of conducting field testing for drugs of abuse.


Gas chromatographic determination of 2,5-hexanedione in urine as an indicator of exposure to n-hexane.

A sensitive and specific method for determination of 2,5-hexanedione in urine is described. Treatment of the urine specimen directly with n-butylamine yields n-butyl 2,5-dimethyl pyrrole. The latter is extracted into diisopropylether and analyzed by gas chromatography (GC) with flame ionization detection (FID), thermionic specific detection (TSD) (N mode), or mass spectrometric detection (MS). The minimum detectable quantities are 1 mg/L urine when employing FID with a coefficient of variation of less than 6%. Recovery of 2,5-hexanedione added to the urine at the level of 10 mg/L was 78.9%.


Rapid high-performance liquid chromatographic assay of chlorophacinone in human serum.

A simple procedure for the determination of chlorophacinone in human serum by high-performance liquid chromatography is reported. After addition of a suitable internal standard, unknown samples were extracted at acid pH with ethyl acetate. The reconstituted methanolic extract was directly injected into the liquid chromatograph. Separation was performed with a Lichrospher C18 5-microns column with a methanol-phosphate buffer (85:15, v/v) mobile phase. The eluent was monitored with UV detection at 286 nm. The method was found to be sufficiently rapid, reproducible, selective, and sensitive for use in clinical and experimental pharmacokinetic studies. Application of this method to 20 intoxicated patients indicated that the risk of bleeding syndrome, which is always associated with this kind of intoxication, is no longer present when chlorophacinone levels drop to below 1 microgram/mL.


Determination of 3-quinuclidinyl benzilate (QNB) and its major metabolites in urine by isotope dilution gas chromatography/mass spectrometry.

In response to the scheduled destruction of U.S. military stockpiles of the hallucinogenic agent 3-quinuclidinyl benzilate (QNB), a specific confirmatory test for human exposure to QNB was developed. The amount of the parent compound in the urine as well as the two major metabolites, 3-quinuclidinol (Q) and benzilic acid (BA), was determined because the relationship between QNB dose and levels of QNB and its metabolites in human urine is not known. QNB was determined in urine samples spiked at a target level of 0.5 ng/mL, and the metabolites BA and Q were determined at a target level of 5 ng/mL. The method uses solid-phase extraction to isolate each analyte from the urine and isotope dilution gas chromatography/mass spectrometry for quantitation. Each analyte is converted to its trimethylsilyl derivative for analysis. The analytical method was tested on eight different urine samples spiked with known amounts of the analytes near the target levels, at 10 times the target levels, and blank (unspiked) urine samples. The variabilities in the method are for the most part evenly distributed between three imprecision categories: GC/MS measurement, sample preparation, and the urine samples. The total imprecision (1 standard deviation) of a single measurement is about 15% of the value for each analyte.


Detection of diuretics in horse urine by GC/MS.

The use of diuretics in horses subject to doping control is prohibited. Thus, a sensitive screening procedure is required to identify the chemically different diuretics. We communicate here a method to detect three commonly employed acidic diuretics: bumetanide, ethacrynic acid, and furosemide. A liquid-liquid extraction on Extrelut 3 was performed at weak acidic and basic conditions using ethyl acetate as organic solvent. For analysis by GC, the diuretics were methylated on-column in the presence of MSTFA/TMAH, avoiding the commonly employed highly toxic derivatizing agent methyl iodide. For identification of diuretics, we used a mass selective detector operating in the SIM (selected ion monitoring) mode. Confirmation analysis may be obtained with a full scan run. Recoveries for the individual drugs ranged from 31 to 48% at the 100-ng/mL level for 3 mL urine, using calibration curves of drug standards with linearity from 2.5 to 20 ng injected. The limit of detection amounts to 40 ng/mL for the three diuretics. The method permits rapid and sensitive detection of diuretics in horse urine and is recommended for doping control.


The effect of pralidoxime chloride in the assay of acetylcholinesterase using 5,5'-dithio-bis(2-nitrobenzoic acid) (Ellman's reagent).

Pralidoxime chloride (PAM) hydrolyzes acetylthiocholine, the substrate used in the assay of red cell cholinesterase. The thiocholine that is produced forms a yellow complex when Ellman's reagent is used in the assay. This was tested in blood samples of patients who were treated with PAM after organophosphorus (OP) poisoning and after the observation of an immediate increase in absorption of light at 412 nm.


Vascular fluid mechanics, the arterial wall, and atherosclerosis.

Atherosclerosis, a disease of large- and medium-size arteries, is the chief cause of death in the United States and in most of the western world. Severe atherosclerosis interferes with blood flow; however, even in the early stages of the disease, i.e. during atherogenesis, there is believed to be an important relationship between the disease processes and the characteristics of the blood flow in the arteries. Atherogenesis involves complex cascades of interactions among many factors. Included in this are fluid mechanical factors which are believed to be a cause of the highly focal nature of the disease. From in vivo studies, there is evidence of hemodynamic influences on the endothelium, on intimal thickening, and on monocyte recruitment. In addition, cell culture studies have demonstrated the important effect of a cell's mechanical environment on structure and function. Most of this evidence is for the endothelial cell, which is believed to be a key mediator of any hemodynamic effect, and it is now well documented that cultured endothelial monolayers, in response to a fluid flow-imposed laminar shear stress, undergo a variety of changes in structure and function. In spite of the progress in recent years, there are many areas in which further work will provide important new information. One of these is in the engineering of the cell culture environment so as to make it more physiologic. Animal studies also are essential in our efforts to understand atherogenesis, and it is clear that we need better information on the pattern of the disease and its temporal development in humans and animal models, as well as the specific underlying biologic events.(ABSTRACT TRUNCATED AT 250 WORDS)


Cocaine and metabolite concentrations in the hair of South American coca chewers.

Hair samples obtained from South American Indians who were identified as daily chewers of coca leaves were analyzed by a sensitive gas chromatography/mass spectrometry (GC/MS) method for cocaine, benzoylecognine (BE), and ecognine methyl ester (EME). The mean cocaine concentration in the hair of these five subjects was 15.2 ng/mg hair +/- 11.0 (range = 1.0-28.9 ng/mg), mean BE concentration was 2.8 +/- 1.6 ng/mg hair (range = 0.3-4.4 ng/mg hair), and mean EME concentration was 1.6 +/- 1.7 (range = 0.0-4.4 ng/mg hair). The finding that cocaine was present at approximately 5 times higher concentration than BE and approximately 12 times higher than EME is surprising in light of the much longer plasma half lives of these metabolites. Washing the hair before analysis with 1% dodecyl sulfate, methanol, and distilled water reduced the concentration of cocaine in the hair but also reduced the concentrations of the metabolites. These data suggest that factors other than the drug concentration in blood may be important in determining the amount of drug incorporated into hair.


Evaluation of full-scanning GC/ion trap MS analysis of NIDA drugs-of-abuse urine testing in urine.

Analytical methods developed for the Finnigan MAT ITS40 gas chromatograph-ion trap mass spectrometer (GC/MS) were evaluated for the confirmation of drugs-of-abuse in urine. The specific drugs evaluated are those listed by the National Institute on Drug Abuse (NIDA): 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (9-carboxy-THC), benzoylecgonine (BE), codeine and morphine, phencyclidine (PCP), amphetamine, and methamphetamine. Drugs were extracted from urine using solid-phase columns, separated by capillary gas chromatography, and analyzed by ion trap mass spectrometry following electron impact ionization. All drugs except PCP were derivatized prior to analysis. The full scan limits of detection (LOD), quantitation (LOQ), and linearity were 2.5, 5.0, and 1000 ng/mL, respectively, for 9-carboxy-THC; 37, 75, and 5000 ng/mL for BE; 50, 100, and 2500 ng/mL for the opiates; 0.25, 0.50, and 500 ng/mL for PCP; and 50, 100, and 5000 ng/mL for the amphetamines. The limits of detection (LOD) and limits of quantitation (LOQ) met the minimum criteria for the signal-to-noise (S/N) ratio and spectral match criteria for drug identification. Absolute LODs and LOQs (in ng/mL) for the ITS40 based on single ion monitoring of blank urines were: 0.8 and 2.0 for 9-carboxy-THC; 8.9 and 25 for BE; 3.3 and 9.6 for codeine; 6.2 and 16.7 for morphine; 0.25 and 0.32 for PCP; 0.7 and 2.0 for amphetamine; and 2.4 and 5.7, for methamphetamine, respectively. The coefficient of variation ranged from 5 to 10%, and analytical recoveries were in the range of 90-114%. The ion trap mass spectrometer permits full scan identification of drugs while maintaining analytical LOQ that are below NIDA guidelines, and has equivalent or better detection limits to quadrupole analyzers for high sensitivity applications.


Topographical mapping of sites of enhanced HRP permeability in the normal rabbit aorta.

The spatial distribution of sites of enhanced permeability to the macromolecule horseradish peroxidase (HRP) in the normal rabbit aorta after one min circulation was studied using image analysis. These sites, referred to as "HRP spots," exhibit a nonuniform distribution that is qualitatively similar in all rabbits studied. The density of HRP spots is highest in the aortic arch, decreases distally, reaches a minimum in the lower descending thoracic aorta, and then increases again in the abdominal aorta. The region of highest spot density follows a clockwise helical pattern in the aortic arch and outside the arch occurs in streaks largely oriented in the bulk flow direction. The streaks in the abdominal aorta localize along the anatomical right lateral wall and occasionally along the left lateral wall proximal to the celiac artery and along the ventral wall between the celiac and superior mesenteric arteries. The density of spots is high in the immediate vicinity of aortic ostia with the most elevated density being distal to ostia in most cases. At a short distance from the ostium edge of the celiac and superior mesenteric branches the proximal density is comparably high, and no preferred spot orientation is observed around the brachiocephalic vessel. These results are consistent with an influence of localizing factors such as detailed hemodynamic phenomena and/or arterial wall structural and/or functional variations.


The polyelectrolyte properties of elastin.

The charge structure and ionic interactions of elastin prepared from the pig thoracic aorta by acid, alkali, or CNBr extraction have been investigated by potentiometric titration and radiotracer techniques. The number of charged groups was consistent with the amino acid composition, comparable to elastin from other sources and insensitive to the method of preparation. The enthalpies of ionization of the basic groups were comparable for those previously found for proteins but those of the acidic groups were higher. Ionic interactions were predominantly electrostatic although a strong affinity for chloride ions was noted. Changes in ionic interactions as the elastin was stretched had a similar effect to an increase in the apparent fixed charge density of the tissue. Mechanical strain altered the protonation of the elastin and the pK of the carboxyl groups. Conversely, the conformation of the elastin network varied with ionic strength and pH, being particularly sensitive to the degree of ionization of the more basic groups and with the ionic strength and anion composition of the medium. We speculate that strain induced changes in the conformation of elastin altering its reactivity towards lipids, ions or matrix macromolecules or changes in its mechanical properties resulting from changes in its ionic environment may be of physiological or pathological importance.


Endothelial cell morphometry of atherosclerotic lesions and flow profiles at aortic bifurcations in cholesterol fed rabbits.

Observations on shapes of endothelial cells both in sudanophilic and nonsudanophilic regions at bifurcations of the brachiocephalic (BC) and left subclavian (SA) arteries in hyperlipidemic rabbits were performed under a SEM. The stagnation point of flow and leading edges of flow dividers were nonsudanophilic and covered by round and long fusiform endothelial cells, respectively. The hips of flow dividers of both branchings, proven to be relatively low shear stress regions, by movement of microspheres in steady flow, were sudanophilic and covered by ellipsoidal cells. Similar studies were carried out in normolipidemic rabbits. It might be concluded that lipid deposition in hyperlipidemic rabbits occurs in relatively low shear stress regions, where endothelial cells are functionally activated, rather than in laminar high shear stress regions at the flow divider.


The distribution of fluid forces on model arterial endothelium using computational fluid dynamics.

Numerical calculations are used in conjunction with linear perturbation theory to analyze the problem of laminar flow of an incompressible fluid over a wavy surface which approximates a monolayer of vascular endothelial cells. These calculations model flow conditions in an artery very near the vessel wall at any instant in time, providing a description of the velocity field with detail that would be difficult to identify experimentally. The surface pressure and shear stress distributions are qualitatively similar for linear theory and numerical computations. However, the results diverge as the amplitude of surface undulation is increased. The shear stress gradient along the cell model surface is reduced for geometries which correspond to aligned endothelial cells (versus nonaligned geometries).


Convective mass transfer effects on the intracellular calcium response of endothelial cells.

Endothelial cells, which line the vasculature, respond to specific agonists such as adenosine triphosphate (ATP) by elevating cytosolic calcium levels and increasing production of the vasoactive compounds, prostacyclin and endothelial derived relaxing factor (EDRF). Endothelial cells express ecto-enzymes which metabolize ATP. If the activity of these enzymes is sufficiently high, then the concentration of ATP near the endothelial cell surface can be substantially lower than the bulk concentration. The ATP concentration is determined by a balance between the convection of fresh ATP from upstream and the degradation of ATP by the endothelial cells. In this report, we present a parallel plate flow system for measurement of cytosolic calcium levels ([Ca2+]i) of individual bovine aortic endothelial cells with the calcium sensitive fluorescent dye, fura-2. The cells respond to increases in the flow rate by increasing [Ca2+]i if there is ATP present in the perfusing buffer, but not in the absence of ATP. The amount of agonist in the perfusing fluid near the endothelial cell surface is estimated by solving the governing differential equation for the concentration profile of ATP in the parallel plate flow geometry. The solution indicates that one mechanism endothelial cells may use to detect changes in the flow rate is to respond to the change in the local concentration of agonist.


Computer simulation of occupant neck response to airbag deployment in frontal impacts.

A mathematical simulation was performed to study the potential of head and neck injury to an unbelted driver restrained by an airbag. The baseline study represented a 50th percentile male dummy driving in a compact car with the steering wheel perpendicular to the floor. The vehicle was moving at 48 km/hour at the time of impact. Model predictions were compared with sled test results. The data agreed reasonably well. A parametric study was performed to study the effect of changing the steering wheel angle and the size of the airbag. It was found that when the standard 20 degrees angle steering wheel was used, neck joint torques were decreased by 22 percent while the resultant head acceleration increased 41 percent from the base line study. When the vertical dimension of the airbag was reduced by 10 percent, neck joint torques were increased by 14 percent, while head acceleration showed a slight decrease of 9 percent.


Mechanical properties of the rabbit patellar tendon.

The mechanical and structural properties of the patellar tendon fascicle-bone units of rabbit knees were determined by tensile tests, particularly focusing on their local differences. There were no significant differences in the strains measured by a video dimension analyzer among the proximal, middle, and distal regions of the central portion of tendon. The mechanical properties of the medial portion agreed well with those of the central portion. However, significant differences were observed in the tensile strength between the lateral and the other two portions: the tensile strength of the lateral portion was about 16 percent larger than those in the other portions.


A force-indentation relationship for gymnastic mats.

The mechanical properties of a series of gymnastic surfaces are investigated. A Force--Indentation relationship is obtained for each surface. This law can be used to simulate the ground reaction force during under-foot impact with a gymnastic surface. The law is independent of many of the properties of the striking body and when incorporated into a system of differential equations describing the motion of the impacting body, can be used to compute system responses and to investigate the importance of different properties of the various surfaces. Several examples, using both a single, rigid mass and a four link, articulated system are presented, and demonstrate that the relationship can be satisfactorily incorporated into a solution algorithm for a large-displacement dynamical analysis.


A parametric study of the thoracic injury potential of basic taekwondo kicks.

A parametric investigation of the thoracic injury potential of basic taekwondo kicks was conducted through the use of computer simulations. Linkage-based models were employed to simulate the kinetics of the kicking leg and were used to drive a human thorax model. The results of the analysis according to the thoracic compression criterion indicated a minimal probability of severe injury (AIS4+) for swing kicks, nearly 0 percent and thrust kicks, less than three percent. The thoracic viscous criteria, on the other hand, predicted a severe injury probability of up to 100 percent for swing kicks and up to 80 percent for thrust kicks. Additional analysis showed that the injury potential was a strong function of the kick velocity and a weak function of the applied constant force. The injury potential was also found to be a weak function of the size and weight of the kicking leg, with variations in the peak compression and viscous response being typically below 5 percent for a 20 percent change in either the mass or the length.


Contact stress gradient detection limits of Pressensor film.

Fuji Pressensor film has been widely used for measurement of contact stresses in articular joints. In relatively smooth contact fields, measurement errors are reported to be in the range of approximately 10-15 percent. However, when local incongruities exist, strong contact stress gradients are present. This study investigates the film's capability to accurately transduce such gradients. Standardized stress distributions were produced by compressing the film between a rigid cylinder and an elastic layer supported by a rigid substrate. Seven different cylinder radii were used to obtain a range of gradient magnitudes. The resulting stains were digitized, and the contact stress gradients assessed by image analysis. Experimentally detected gradients were compared with those predicted analytically. The film's capability to reliably transduce contact stress gradients was shown to be sufficient for usage in the study of typical local articular incongruities.


Boundary element method analysis for the bioheat transfer equation.

In this paper, the boundary element method (BEM) approach is applied to solve the Pennes (1948) bioheat equation. The objective is to develop the BEM formulation and demonstrate its feasibility. The basic BEM formulations for the transient and steady-state cases are first presented. To demonstrate the usefulness of the BEM approach, numerical solutions for 2-D steady-state problems are obtained and compared to analytical solutions. Further, the BEM formulation is applied to model a conjugate problem for an artery imbedded in a perfused heated tissue. Analytical solution is possible when the conduction in the x-direction is negligible. The BEM and analytical results have very good agreement.


A three-dimensional variable geometry countercurrent model for whole limb heat transfer.

A new formulation of the combined macro and microvascular model for heat transfer in a human arm developed in Song et al. [1] is proposed using a recently developed approximate theory for the heat exchange between countercurrent vessels embedded in a tissue cylinder with surface convection [2]. The latter theory is generalized herein to treat an arm with an arbitrary variation in cross-sectional area and continuous bleed off from the axial vessels to the muscle and cutaneous tissue. The local microvascular temperature field is described by a "hybrid" model which applies the Weinbaum-Jiji [3] and Pennes [4] equations in the peripheral and deeper tissue layers, respectively. To obtain reliable end conditions at the wrist and other model input parameters, a plethysmograph-calorimeter has been used to measure the blood flow distribution between the arm and hand circulations, and hand heat loss. The predictions of the model show good agreement with measurements for the axial surface temperature distribution in the arm and confirm the minimum in the axial temperature variation first observed by Pennes [4] for an arm in a warm environment.


Strain fields on cell stressing devices employing clamped circular elastic diaphragms as substrates.

Solutions are presented for the surface strain fields on inflated elastomeric circular diaphragms used for in vitro cell stressing experiments. It is shown, by using the method developed by Way (1934) to solve the nonlinear von Karman plate equations, that the surface strains due to bending are not negligible and that large negative radial strains arise near the clamped edge for center deflection-to-thickness ratios (w/h) less than 10. The method of Hart-Smith and Crisp (1967) was used for w/h greater than 10 to solve the nonlinear equations for symmetrical deformation of axially symmetrical rubber-like membranes. In the membrane solutions the circumferential strains drop parabolically to zero at the clamped edge of the diaphragm, while the radial strains increase slightly with the radius. The solutions for w/h greater than 10 are compared to optical measurements of in-plane displacements used to calculate the circumferential strains on the diaphragm, yielding excellent agreement with the theory.


A numerical study of the shape of the surface separating flow into branches in microvascular bifurcations.

The shape of the separating surface formed by the streamlines entering the branches of microvascular bifurcations plays a major role in determining the distribution of red blood cells and other blood constituents downstream from the bifurcation. Using the finite element method, we determined the shape of the surface through numerical solution of three dimensional Navier-Stokes equations for fluid flow at low Reynolds numbers in a T-type bifurcation of circular tubes. Calculations were done for a wide range of daughter branch to parent vessel diameter ratios and flow ratios. The effect of Reynolds number was also studied. Our numerical results are in good agreement with previously reported experimental data of Rong and Carr (Microvascular Research, Vol. 39, pp. 186-202, 1990). The numerical results of this study will be used to predict the concentration of blood constituents downstream from microvascular bifurcations providing that the inlet concentration profile is known.


Shear stability of an elastomeric disk spacer within an intervertebral joint: a parametric study.

A parametric study was conducted to compare the resistance to shear force provided by three surgical implantation techniques and three endplate designs for use with a polymeric lumbar intervertebral disk spacer. While under an axial load, the implant was pushed out laterally through the surgical window created for implantation. Force at 0.3 mm displacement, slope of the initial portion of the force-displacement graph, and maximum force were measured. The results indicate that implants with pegs, inclined planes, or domes on the surfaces of the disk will add significantly to the shear stability of the implant while maintaining the simplicity of a single part device.


Pressure drops through arterial stenosis models in steady flow condition.

Measures of pressure drops were made in two different plexiglass models of axial-symmetric arterial stenoses. The stenosis models had the same area reduction (86 percent) but were of different length so as to have a different tapering degree. Pressures were measured in steady flow condition at three equidistant points of the stenosis: upstream, in the middle, and downstream. Results indicate that: the upstream-middle pressure drop is independent of tapering degree but is highly influenced by area reduction; moreover it is much greater than the middle-downstream drop. The upstream-middle pressure drop can be accurately predicted by means of a relationship deduced by the momentum equation.


Adaptative control of above knee electro-hydraulic prosthesis.

Conventional designs of an above-knee prosthesis are based on mechanisms with mechanical properties (such as friction, spring and damping coefficients) that remain constant during changing cadence. These designs are unable to replace natural legs due to the lack of active knee joint control. Since the nonlinear and time-varying dynamic coupling between the thigh and the prosthetic limb is high during swing phase, an adaptive control is employed to control the knee joint motion. Two dimensional simulation indicates that the adaptive controller can improve the appearance of gait pattern. It is adaptable to walking speed and can compensate for the variations of hip moment, hip trajectory and toe-off conditions.


Lung transplantation.

Advances in solid organ transplantation over the last several decades have made human lung transplantation a realistic possibility for selected patients with end-stage lung disease. A review of clinical indications, proper patient selection, and long-term management is presented. Infection and rejection continue to represent 2 major areas of posttransplantation complications and merit particular attention.


Influence of azelastine and some selected drugs on mucociliary clearance.

The effect of azelastine and some selected compounds on ciliary beating frequency (CBF) was investigated in vitro using human mucosal samples and in vivo using anesthetized guinea pigs. Further influence of azelastine on mucus secretion was evaluated in mice and on mucociliary clearance in anesthetized rabbits. Azelastine influenced the ciliary beating frequency neither in vitro nor in vivo. Azelastine, similarly to salbutamol, ambroxol, and bromhexine, increased mucus secretion measured by the tracheal output of phenol red. Azelastine dose-dependently enhanced mucociliary clearance measured by elimination of 99mTc-labeled erythrocytes in rabbits. The activity of azelastine proved to be about 10 times stronger than that of bromhexine. Since the ciliary activity remained unchanged under the influence of azelastine, it is likely that azelastine increases the mucociliary clearance by enhancing bronchial secretion. It is possible that the observed increase in mucociliary clearance may contribute to the beneficial effect of azelastine in the treatment of respiratory diseases.


Hyaluronan (hyaluronic acid) in lung lavage of asbestos-exposed humans and sheep.

The concentration of hyaluronan was measured in the bronchoalveolar lavage fluid (BALF) of 18 control subjects and 27 workers from the asbestos mills and mines of Québec, 9 without asbestosis and 18 with asbestosis. Hyaluronan was also measured in the BALF of 9 control sheep exposed to 100 ml phosphate-buffered saline (PBS) at 10 day intervals for 39 months, and 13 sheep exposed at the same intervals to 100 mg chrysotile in 100 ml PBS for 24 months. At month 24, the asbestos-exposed sheep were classified into 3 groups: (A) 4 sheep exposed to PBS alone, (B) 4 sheep exposed to 10 mg chrysotile asbestos every 10 days, and (C) 5 sheep exposed to 100 mg chrysotile asbestos every 10 days for 15 months. The BALF hyaluronan averaged 53.9 +/- 7.4 ng/ml in human controls, 67.5 +/- 10.3 ng/ml in asbestos-exposed workers without asbestosis, and 206 +/- 83 ng/ml in workers with asbestosis (p less than 0.05 vs. normal). In the control sheep, BALF hyaluronan was 34.7 +/- 6.9 ng/ml, and it was 31.5 +/- 17.8 ng/ml in the low-dosage asbestos-exposed group (A), 83.0 +/- 27.7 ng/ml in the intermediate-dose group (B), and 248.0 +/- 134.7 ng/ml in the high-dosage group (C) (p less than 0.05 vs. controls). In contrast, the release of plasminogen activator, a protease that may play a role in limiting the fibrotic process, was increased in group A, but not in groups B and C. In conclusion, BALF hyaluronan constitutes an indicator of lung interstitial tissue changes that may reflect the activity of the fibrosing alveolitis associated with chronic asbestos exposure.


Later development of asthma in patients with a negative methacholine inhalation challenge examined for suspected asthma.

A negative methacholine inhalation challenge (MIC) in a patient with suspected bronchial asthma is generally considered to make this diagnosis unlikely. Nevertheless, the patient may later develop asthma. To estimate the proportion that eventually becomes asthmatic, a 10 year follow-up study was carried out on 334 consecutive MIC-negative patients aged 14-80 years. The development of asthma among these patients was assessed on the basis of entitlement to preferential refund from the cost of antiasthmatic therapy granted for them under national health insurance. During the follow-up 30 patients (9%) were granted the refund. There was no significant difference between men and women in this respect. Patients who developed asthma were somewhat older than those who did not. A family history of allergy, allergic rhinitis, and positive reactions to skin prick tests were significantly more common in patients with future asthma. These patients also had a lower mean forced expiratory volume in 1 sec (FEV1) (% of predicted) and a higher mean increase in PEF after an inhaled sympathomimetic than those remaining free from asthma. In multivariate analyses with a logistic model, 3 risk indicators proved independent predictors of future asthma: age, positive family history of allergy, and FEV1 (% of predicted).


K+ channel openers and insulin release.

Recent in vivo and in vitro experiments suggested that the smooth muscle relaxation mediated by diverse pharmacologic agents resulted from K+ channel opening. Pinacidil, cromakalim, nicorandil, RP 49356, minoxidil sulfate and diazoxide belong to this new group of smooth muscle relaxants: the "K+ channel openers". Because modifications in the K+ permeability are known to represent a critical event in the insulin-releasing process, numerous studies have been performed in order to examine the putative effects of K+ channel openers on B-cell function. The aim of the present review is to summarize these experimental data which are sometimes divergent.


Human chorionic gonadotropin causes an estrogen-mediated induction of rat ovarian carbonyl reductase.

We earlier reported that human chorionic gonadotropin (hCG) stimulates rat ovarian carbonyl reductase (CR) activity and content, and that estrogen enhances the stimulatory effect. The present study was performed to determine the mode of action of the gonadotropin. Cycloheximide (CHX) and actinomycin D (AD) were given to estradiol-pretreated immature rats 6 h before hCG treatment. The enzyme activity was measured with three substrates, and the enzyme content was determined by the method of Western-blot analysis using anti-rat ovarian CR anti-serum as the first antibody. Both protein inhibitors significantly prevented hCG from increasing the enzyme activity and content in estradiol-pretreated ovary. These results indicate that rat ovarian CR is induced by LH via the action of estrogen.


Contrasting effects of pituitary adenylate cyclase activating polypeptide (PACAP) on in vivo and in vitro prolactin and growth hormone release in male rats.

Pituitary adenylate cyclase activating polypeptide (PACAP) is produced by hypothalamic neurons which terminate within the median eminence suggesting that it may be a hypophysiotropic hormone. However, little endocrine activity has been ascribed to the peptide. Therefore we studied the effects of PACAP on prolactin (Prl) release from dispersed cultivated rat pituitary cells in vitro using conventional cultures as well as the reverse hemolytic plaque assay (RHPA). Furthermore the effects of the peptide on in vitro GH release were assessed. In addition, the activity of the peptide on in vivo release of Prl and GH was studied in hypothalamus-lesioned animals. PACAP dose dependently inhibited Prl release form dispersed pituitary cells in both, monolayer cell cultures and the RHPA, whereas GH secretion was not affected. In hypothalamus-lesioned rats which have high Prl levels due to the absence of hypothalamic dopamine, PACAP further stimulated Prl release. Serum GH increased more than 20 fold in response to the intravenous PACAP infusion. Thus in vitro (inhibition of Prl release, no effect on GH release) and in vivo (stimulation of both hormones) experiments yielded contradicting effects of PACAP on pituitary hormone release. We suggest that PACAP may stimulate the release of a paracrine, yet unknown factor which in the intact pituitary overrides the direct inhibitory action of PACAP on the lactotropes. The same or another paracrine factor may also enhance in vivo GH release. In cell culture the paracrine factor is diluted by the medium. Therefore the peptide never reaches effective concentrations which are present within the intact pituitary tissue.


Effects of ketanserin on DOI-, MCPP- and TRH-induced prolactin secretion in estrogen-treated rats.

The effects of ketanserin (Ket), a serotonin (5-HT2) receptor antagonist, on DOI- and mCPP-, two 5-HT agonists, and TRH-induced PRL secretion were studied. Adult female Sprague-Dawley rats ovariectomized for two weeks and treated with a long-acting estrogen, polyestradiol phosphate for one week were used. Drug administration and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before the experiment. Both DOI (0.5 mg/kg BW) and mCPP (1 mg/kg BW) stimulated prolactin secretion within 10 min after iv injection and the effects were diminished by 30 min. In animals pretreated with Ket (5 mg/kg BW, sc), the effect of DOI was blocked, while that of mCPP was augmented. Co-administration of Ket (1 mg/kg BW, iv) with DOI or mCPP produced similar effect. Pretreatment with Ket, similar to sulpiride (Sulp), a dopamine antagonist, potentiated the TRH-induced prolactin secretion. Co-administration of Ket and Sulp further potentiated the TRH action. It is concluded that Ket not only acts as a 5-HT2 receptor antagonist that blocks the action of DOI, but may also act on dopamine receptor(s) with lower sensitivity to Sulp.


Dantrolene stimulates renin secretion by rat renal cortical slices but fails to block calcium-dependent inhibition.

Calcium (Ca) is an inhibitory second messenger in renin secretion, and it has been proposed that some first messengers, such as angiotensin II (A-II), antidiuretic hormone (ADH), and N6-cyclohexyladenosine (CHA), increase Ca and thereby inhibit renin secretion by mobilizing Ca from intracellular sequestration sites. The present experiments were designed to test this proposal by using dantrolene, an antagonist of intracellular Ca mobilization. Dantrolene stimulated renin secretion by rat renal cortical slices in a concentration dependent manner; at 0.0, 0.1, and 0.5 mM dantrolene, secretory rates were 8.1 +/- 0.6, 9.4 +/- 0.6 (p less than 0.05), and 14.9 +/- 1.2 (p less than 0.0001) GU/g x hr, respectively. These results could be interpreted to mean that Ca mobilization is occurring at a finite rate during the basal state, and that by antagonizing this process, dantrolene lowers intracellular Ca and thereby stimulates renin secretion. However, 0.1 mM dantrolene failed to antagonize the inhibitory effects on renin secretion of A-II, ADH, and CHA, and only CHA-induced inhibition of renin secretion was antagonized by 0.5 mM dantrolene. We conclude that if A-II, ADH, and CHA inhibit renin secretion by mobilizing Ca from an intracellular storage site, then the site is insensitive to dantrolene.


Decreased levels of muscarinic receptors in bladders from the alcohol preferring rat line.

The Bmax for [3H]QNB binding in the bladders of alcohol preferring (AA) rats was only approximately 60% of that in the alcohol non-preferring (ANA) rats. No significant change in Bmax for [3H]QNB binding in bladder was observed between alcohol insensitive (AT) and alcohol sensitive (ANT) rats. No significant change in Kd for [3H]QNB binding in bladder was observed between the four different rat lines studied. Therefore, alcohol preference but not sensitivity is associated with a decrease in muscarinic receptor density in the rat bladder. Because all of the rats used in this study were ethanol-naive, the decrease in muscarinic receptor density in the bladders of alcohol preferring rats is associated with genetic factors inherent to this rat line. Further studies are needed to determine if these observations are tissue specific or specific to the m2 subtype, which predominates in the rat bladder.


Ibogaine reduces amphetamine-induced locomotor stimulation in C57BL/6By mice, but stimulates locomotor activity in rats.

The effect of ibogaine hydrochloride on locomotor stimulation induced by d-amphetamine sulfate was tested in male C57BL/6By mice and in female Sprague-Dawley rats. In mice, locomotor stimulation induced by d-amphetamine at 1 or 5 mg/kg s.c. was reduced by prior administration of one or two injections of ibogaine (40 mg/kg), given 2 or 18 hours earlier. This reduction in locomotor activity persisted for two days. Locomotor stimulation induced by a higher dose (10 mg/kg) of d-amphetamine was not reduced by such prior administration of ibogaine. A lower dose of ibogaine (20 mg/kg) did not reduce the subsequent locomotor activity induced by d-amphetamine. Ibogaine decreased striatal dopamine levels, while d-amphetamine increased them. Ibogaine treatment (2 x 40 mg/kg, 18 hours apart) induced a decrease by 30% in the level of striatal dopamine and its metabolites measured in tissue extracts 3 hours after the second ibogaine injection. One hour after d-amphetamine (5 mg/kg) administration, the level of striatal dopamine increased by 26%. Although the level of striatal dopamine was initially lower in the ibogaine-pretreated mice, d-amphetamine (5 mg/kg) administration induced an increase in striatal dopamine and its metabolites. The effect of ibogaine seems to be species specific, since in rats pretreated with ibogaine 18 hours before d-amphetamine, locomotor stimulation induced by d-amphetamine was further increased. In addition, the in vitro electrical-evoked release of [3H]dopamine from striatal tissue was either unchanged or inhibited in the presence of d-amphetamine, and after ibogaine pretreatment in vivo, the release of tritium in the presence of d-amphetamine was inhibited or stimulated in mice and rats, respectively.


The effect of cobrotoxin on cholinergic neurons in the mouse.

By using multiple time-point constant-rate infusions of deuterium-labeled phosphorylcholine, appropriate kinetic parameters were obtained for use in the calculation of the turnover rate of acetylcholine (TRACh) in selected mouse brain regions. After obtaining these data, the relationship between the analgesic agent cobrotoxin (CT) and the activity of central cholinergic neurons was investigated by determination of TRACh in selected mouse brain regions 3 hours following intracerebroventricular (i.c.v.) injection of CT. There were no obvious changes in the concentrations of ACh and choline (Ch) in the cortex, hippocampus, hypothalamus, midbrain, striatum, or thalamus of the mouse after injection of an analgesic dose of CT (2 micrograms, i.c.v.). TRACh in the thalamus and the striatum were significantly increased, as compared to controls. On the other hand, i.c.v. injection of CT was found to significantly reduce TRACh in the hippocampus and midbrain. These results suggest that the activity of hippocampal and midbrain cholinergic neurons is suppressed by CT, whereas the activity of striatal and thalamic cholinergic neurons is increased by CT at a time when a maximum analgesic response to CT is expressed.


Effect of chronic administration of dexfenfluramine on blood pressure in salt-sensitive rats.

Chronic administration of dexfenfluramine, at a relatively low daily dose, slowed the development of salt-induced elevation of blood pressure in salt-sensitive (Dahl DS and Rapp SS) rats. This effect could not be accounted for by drug-related anorexia alone. Elevated serotonin activity, possibly in the brain, may underlie this antihypertensive action of dexfenfluramine.


Inhibition of immunoreactive growth hormone secretion from lymphoid cell lines by dexamethasone.

The regulation of irGH secretion by the immune system was examined using lymphoid cell lines, H9 and IM9. Using a highly sensitive immunoassay, irGH secretion by H9 was negatively regulated by dexamethasone, whereas many other regulators of hGH secretion, including hormones, monoamines, and second messenger, had no measurable effect on irGH secretion. Treatment of H9 cells with dexamethasone for 48 hours could cause as high as 70% reduction in irGH secretion without affecting either cell numbers or viability. Using IM9, neither growth hormone releasing hormone nor thyrotropin releasing hormone had significant effect on either irGH steady-state level transcripts or irGH secretion. These findings suggest that irGH secretion by lymphocytes was regulated in a different manner from that by pituitary cells.


Stimulation of sulfated glycosaminoglycan synthesis by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+.

Glycyl-L-histidyl-L-lysine-copper (II) complex (GHK-Cu) is a naturally occurring tripeptide with potential healing properties. We studied the effect of GHK-Cu on the synthesis of glycosaminoglycans (GAGs) by normal human fibroblasts in culture. Cells were incubated with 3H glucosamine and 35S sulfate and the radioactivity of isolated GAGs was determined. GHK-Cu induced a dose-dependent increase of the synthesis of total GAGs secreted into the culture medium and those associated with the cell layer. The effect of GHK-Cu was biphasic with a maximal stimulation at 10(-9) to 10(-8) M. At higher concentrations, the rate of synthesis returned progressively to that of control cultures. Electrophoretic analysis of the different GAG populations showed that GHK-Cu preferentially stimulated the synthesis of extracellular dermatan sulfate and cell layer associated heparan sulfate. No influence of GHK-Cu on the synthesis of hyaluronic acid was observed. GHK-Cu stimulation of GAG synthesis may be one of the phenomenons implicated in the wound healing properties of the peptide.


Relationship between hypothalamic noradrenergic activity and the sympathetic activity in interscapular brown adipose tissue after cold-swim stress in rats.

Noradrenaline (NA) activities in both hypothalamus and interscapular brown adipose tissue (IBAT) were simultaneously assessed before and after cold-swim stress in rats. The technique of gas chromatography-mass spectrometry was employed for the analysis of NA and its primary neuronal metabolite, 3,4-dehydroxy-phenylethylenglycol (DHPG), and the ratio of DHPG to NA was used as an index of NA activity. The ratios of DHPG/NA in both hypothalamus and IBAT were significantly elevated 5 and 20 min after cold-swim stress. Moreover, we found that there is a highly significant positive relationship between the hypothalamic DHPG/NA ratio and the ratio of DHPG/NA in IBAT (r = 0.872, p less than 0.0001). This observation strongly supports the concept in which hypothalamic NA neurons play an important role in modulating the sympathetic outflow.


Studies on the intracellular degradation of newly synthesized collagen in 3-methylcholanthrene induced fibrosarcoma cells.

The intracellular degradation of newly synthesized collagen was studied in both normal fibroblast and 3-methylcholanthrene induced fibrosarcoma cells. The degradation of newly synthesized collagen was examined using pulse-chase experiments and radioactive labelling techniques with [3H]-proline. The percentage of intracellular proteolysis of newly synthesized collagen was determined by measuring the formation of [3H]-hydroxyproline containing fragments in alcohol-soluble and insoluble fractions of normal cells and fibrosarcoma cells in the culture. The rate of degradation of newly formed collagen was then followed by estimating the radioactivity of [3H]-hydroxyproline at different intervals, during the chase period. The results clearly demonstrated that the percent of intracellular degradation of newly synthesized collagen was approximately three fold higher in fibrosarcoma cells than in normal fibroblast cells. The increased intracellular degradation of newly formed collagen was followed by an increase in the activity of cathepsin B and L in fibrosarcoma cells. The pulse-chase experiments indicated that the rate of degradation of newly synthesized collagen in fibrosarcoma cells is relatively greater than in normal fibroblast cells. In addition, as the labelling time increased, the formation of [3H]-hydroxyproline containing peptides in the ethanol-soluble fraction were found to be increased in both normal cells and fibrosarcoma cells, but the extent of formation was higher in fibrosarcoma cells compared to normal fibroblast cells. The results of this investigation collectively suggest that the intracellular degradation of newly synthesized collagen is enhanced in fibrosarcoma cells.


Effects of adenosinergic drugs on hypoxia-induced electrophysiological changes in rat hippocampal slices.

The effects of adenosinergic antagonists caffeine and DPCPX, and of the adenosinergic agonists L-PIA, CPA and CGS 21680 were investigated on fully and partially reversible hypoxia-induced electrophysiological changes in rat hippocampal slices. The influence of a high potassium solution and of the N-methyl-D-aspartate antagonist dizocilpine (MK 801) was also tested. The latency to obtain a 50% decrease in the amplitude of the CA1 population spike (CA1 PS) during a short- (5-10 min) lasting hypoxic period was significantly increased (P less than 0.01) by slice perfusion with caffeine (50 microM), DPCPX (0.2 microM), and by increasing (from 3 to 4 mM) the potassium concentration in the medium bathing the hippocampal slices. The latency was significantly decreased (P less than 0.01) by slice perfusion with L-PIA (0.2 microM) and CPA (0.05 microM). It was not significantly modified by CGS 21680 (5 microM). The incidence of reappearance of the CA1 PS during reoxygenation after long- (45 min) lasting hypoxia was significantly increased (P less than 0.05) by slice perfusion with MK 801 (50 microM), while it was not significantly affected by slice perfusion with caffeine (50 microM) or DPCPX (0.2 microM) or L-PIA (0.2 microM) or CPA (0.05 microM) or CGS 21680 (5 microM). The results indicate a prevalent involvement of the A1 adenosine receptors in the early mechanisms underlying hypoxia-induced reversible changes. Adenosine seems to have a limited role in the late mechanisms occurring after a long-lasting hypoxic period.


Effects of prior exposure to cocaine: interaction of reinforcing and suppressant effects.

Squirrel monkeys were trained to respond under second-order schedules of food presentation and then sequentially exposed to either a self-administration (SA) and then a conditioned taste aversion (CTA) procedure, or a CTA procedure and then a SA procedure. Initial exposure to stimuli associated with post-session delivery of cocaine (0.3 mg/kg) either maintained (SA) or suppressed (CTA) responding, respectively. In contrast, following exposure to CTA, SA procedures failed to maintain levels of responding comparable to those seen with initial exposure to SA. Following exposure to SA, the CTA procedure failed to suppress responding. Thus, prior exposure to either the reinforcing or suppressant effects of cocaine modified its subsequent behavioral effects, suggesting a unique role for behavioral history in the abuse potential of cocaine.


Sexual differences in the activity of periventricular-hypophysial dopaminergic neurons in rats.

The activities of periventricular-hypophysial dopaminergic (DA) neurons were compared in male and female rats by measuring dopamine synthesis (accumulation of 3,4-dihydroxyphenylalanine [DOPA] after inhibition of L-aromatic amino acid decarboxylase) and metabolism (concentrations of 3,4-dihydroxyphenylacetic acid [DOPAC]) in terminals of these neurons in the intermediate lobe of the pituitary. For comparison, the synthesis and metabolism of dopamine in the neural lobe of the pituitary and median eminence were also determined. The concentrations of DOPAC and accumulation of DOPA were higher in females than in males in both the intermediate lobe and median eminence, revealing a sexual difference in the basal activity of periventricular-hypophysial and tuberoinfundibular DA neurons. In contrast, there were no differences between male and female rats in activity of DA neurons terminating in the neural lobe. One week following gonadectomy, DOPA accumulation in the median eminence was decreased in females and increased in males, but remained unchanged in the intermediate lobe. These results indicate that sexual differences in the activity of periventricular-hypophysial DA neurons terminating in the intermediate lobe are not dependent upon the presence of circulating gonadal steroids, and in this respect, these neurons differ from tuberoinfundibular DA neurons.


The effect of dietary supplementation with eicosapentaenoic acid on the phospholipid and fatty acid composition of erythrocytes of marmoset.

Adult male marmoset monkeys were fed eicosapentaenoic acid (20:5n-3) as the ethyl ester in diets containing either 32% (reference diet, no added cholesterol) or 7% (atherogenic diet with 0.2% added cholesterol) linoleic acid (18:2n-6) for 30 wk. No changes were seen in the level of phosphatidylcholine (PC) or phosphatidylethanolamine (PE) but minor changes were observed in both the sphingomyelin (SPM) and phosphatidylinositol plus phosphatidylserine (PI+PS) fractions of erythrocyte lipids. The extent of total n-3 fatty acid incorporation into membrane lipids was higher in atherogenic diets (polyunsaturated/monounsaturated/saturated (P/M/S) ratio 0.2:0.6:1.0) than reference diets (P/M/S ratio 1:1:1) and this was true for both PE (33.4 +/- 1.0% vs 24.3 +/- 1.1%) and PC (9.3 +/- 0.5% vs 4.9 +/- 0.3%). Although suitable controls for cholesterol effects were not included in the study, earlier results obtained with marmosets lead us to believe such effects were probably small. Regardless of basic diet (atherogenic, reference), 20:5n-3 was preferentially incorporated into PE (10.8 +/- 0.2%, 6.0 +/- 0.02%) while smaller amounts were incorporated into PC (6.9 +/- 0.4%, 3.2 +/- 0.2%). The major n-3 polyunsaturated fatty acid found in PE in response to dietary 20:5n-3 was the elongation metabolite 22:5n-3 in both the atherogenic (17.7 +/- 0.7%) and reference (14.3 +/- 1.0%) dietary groups; 22:6n-3 levels were less affected by diet (4.7 +/- 0.3% and 3.9 +/- 0.2%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of n-3 and n-6 fatty acids on tumor necrosis factor cytotoxicity in WEHI fibrosarcoma cells.

Modulation by fatty acids of the cytotoxic effect of recombinant tumor necrosis factor alpha (TNF) toward WEHI 164 mouse fibrosarcoma cells has been examined. Preincubating the highly TNF-sensitive WEHI clone 13 cells for 44 hr with 50 mumol/L of 20:5n-3, 22:6n-3, 18:3n-6, 20:3n-6 or 20:4n-6 reduced cell survival 22 hr after challenge with TNF (40 ng/L) by 65%, 72%, 60%, 98% and 85%, respectively. In comparison, 18:3n-3, 18:2n-6 and 18:1n-9 had only negligible effects on TNF-induced toxicity. Different extent of fatty acid incorporation into cell total phospholipids or triglycerides could not explain the observed effects on TNF cytotoxicity, and the enhanced cytotoxicity could therefore not be explained merely by an increased unsaturation of the cell membranes. In addition to the fatty acid supplied, preincubation with 18:2n-6, 18:3n-6 or 18:3n-3 also enriched the cells with 20:2n-6, 20:3n-6 and 20:3n-3, respectively, most likely due to chain elongation. The results suggest that the WEHI cells have a low delta 6 desaturase activity, and that n-6 and n-3 acids must have at least 3 or 4 double bonds, respectively, to enhance TNF cytotoxicity in WEHI cells. Dexamethasone partly inhibited TNF-induced cytotoxicity, while cyclooxygenase, thromboxane synthetase or lipoxygenase inhibitors had no or negligible effects. The antioxidant butylated hydroxyanisole (BHA) completely inhibited TNF-induced cytotoxicity, while the structurally and functionally similar antioxidant butylated hydroxytoluene had no such effect, indicating that BHA does not block TNF cytotoxicity through its antioxidant effect.(ABSTRACT TRUNCATED AT 250 WORDS)


Monoenoic fatty acids in human brain lipids: isomer identification and distribution.

The carbon chain length distribution and the double bond positional isomer composition of the monoenoic fatty acids of the lipids of total human brain tissue have been determined using gas chromatography and gas chromatography/mass spectrometry of the fatty acid methyl and picolinyl esters. The even chain length monoenoic C16 to C28 fatty acids contain predominantly two positional isomer series, the n-7 and n-9 cis homologues, whose relative proportion varies significantly with chain length. The odd chain length long-chain fatty acids consist of n-8 and n-10 isomers, whereas the odd chain length very long-chain (more than 22 carbon) fatty acids are n-7 and n-9 isomers.


Effects of polyphenolic natural products on the lipid profiles of rats fed high fat diets.

Male Wistar rats were fed a high fat diet (HFD) containing 2.5% cholesterol and 16% lard supplemented with polyphenolic natural products namely quercetin, morin or tannic acid (100 mg/rat/day) for 4, 7 and 10 wk. Rats fed HFD without the supplements served as control. The effects of these compounds on blood lipid profiles, enzymes, liver fat and aorta of the rat were studied. In rats fed HFD containing tannic acid, plasma total cholesterol (TC), low density lipoprotein cholesterol (LDLC) and triglyceride (TG) were reduced by 33.3%, 29.6% and 65.1%, respectively, at week 10. High density lipoprotein cholesterol (HDLC) concentration was not altered. Fat deposition was also decreased in the liver of these rats. Morin significantly reduced plasma TG (65.1%) and liver fat only at week 7 while at week 10 it reduced plasma TC and LDLC by 30.9% and 29.3% respectively. The plasma HDLC concentration was increased by 47.3% at week 4 but no effect was seen at weeks 7 and 10. In the rats fed HFD containing quercetin, plasma HDLC was increased by 28.6% at week 7 but at week 10, plasma LDLC was increased by 21.2%. Quercetin did not cause any significant changes on the plasma TC, TG and liver fat at weeks 4, 7 and 10. Plasma alanine aminotransferase, alkaline phosphatase and bilirubin in control and treated groups were not significantly different. However, hepatic lipase activity in rats fed tannic acid was significantly lower. Aortae of all groups of rats showed no abnormalities. The present report indicates that tannic acid and morin are effective in reducing plasma and liver lipids when supplemented with a high fat diet in rats.


Subterminal hydroxylation of lauric acid by microsomes from a marine fish.

Microsomes from the liver of sea bass (Dicentrarchus labrax) were shown to hydroxylate lauric acid at subterminal positions. The cytochrome P-450 system converted lauric acid to several mono-hydroxylated metabolites including omega-1 hydroxylaurate, which was the major metabolite (44% of total products). In addition, omega-2, omega-3, omega-4 and a small amount (2.3%) of omega hydroxylaurates were found. Reaction products were identified using thin-layer chromatography (TLC) and gas chromatography/mass spectrometry (GC/MS). Oxidation reactions were dependent upon O2 and NADPH, and did not occur with boiled microsomes or in the presence of a mixture of CO/O2. Hydroxylation proceeded linearly up to 20 min at 28 degrees C for protein concentrations below 380 micrograms. Treatment of fish with benzo(a)pyrene (BP) (20 mg/kg) drastically increased xenobiotic metabolism (ECOD, EROD and BPMO activities), but no difference in laurate hydroxylase activity was observed between untreated and treated fish. Starvation strongly enhanced laurate hydroxylase activity, and resumption of feeding reduced by half this increase of activity. In all of the experiments we did not observe any modification of the regioselectivity of lauric acid hydroxylation by this microsomal in-chain hydroxylating system. We suggest that cytochrome P-450 enzymes involved in lauric acid and xenobiotics metabolism are regulated independently.


Inhibition of ferrous-induced lipid peroxidation by pyrimido-pyrimidine derivatives in human liver membranes.

The effects of pyrimido-pyrimidine derivatives (dipyridamole, RA-642, and RA-233) on lipid peroxidation, using d-alpha-tocopherol as standard, were studied in enriched membrane fractions from human and rat hepatocytes. Equimolar concentrations of ferrous sulfate and ascorbic acid were used to induce lipid peroxidation. The amount of peroxidized lipids observed in membrane fractions from human liver was smaller than in those from rat liver. In both species, however, pyrimido-pyrimidine derivatives, except for RA-233 in rat liver, inhibited lipid peroxidation dose-dependently in the following sequence: RA-642 greater than dipyridamole greater than d-alpha-tocopherol RA-233.


A sensitive and specific radioimmunoassay for platelet-activating factor.

A platelet-activating factor (PAF) analog with a reactive omega-aldehyde group at the sn-1 position was synthesized. The hapten-thyroglobulin conjugate was used to immunize rabbits to produce specific antibodies to PAF. The purified immunoglobulin G (IgG) fraction was found to bind stereo-specifically to tritiated PAF and to crossreact minimally with lysoPAF, plasmalogens, and other phospholipids. The radioimmunoassay detected as little as 20 pg of PAF per assay tube and was used to explore agonist-induced synthesis of PAF in rabbit neutrophils. Calcium ionophore A23187 at 1 microM induced PAF synthesis peaking at 2 min and reaching basal levels after 5 min. N-Formyl-Met-Leu-Phe (FMLP) at 0.1 microM also stimulated rapid synthesis and degradation of PAF with a peak at 5 min. Both A23187 and FMLP stimulated PAF synthesis in a dose-dependent manner. The radioimmunoassay should be applicable to the quantitation of PAF in biological samples.


Metals and lipid oxidation. Contemporary issues.

Lipid oxidation is now recognized to be a critically important reaction in physiological and toxicological processes as well as in food products. This provides compelling reasons to understand what causes lipid oxidation in order to be able to prevent or control the reactions. Redox-active metals are major factors catalyzing lipid oxidation in biological systems. Classical mechanisms of direct electron transfer to double bonds by higher valence metals and of reduction of hydroperoxides by lower valence metals do not always account for patterns of metal catalysis of lipid oxidation in multiphasic or compartmentalized biological systems. To explain why oxidation kinetics, mechanisms, and products in molecular environments which are both chemically and physically complex often do not follow classical patterns predicted by model system studies, increased consideration must be given to five contemporary issues regarding metal catalysis of lipid oxidation: hypervalent non-heme iron or iron-oxygen complexes, heme catalysis mechanism(s), compartmentalization of reactions and lipid phase reactions of metals, effects of metals on product mixes, and factors affecting the mode of metal catalytic action.


The inhibitory effect of water on the Co2+ and Cu2+ catalyzed decomposition of methyl linoleate hydroperoxides.

The inhibitory effect of water on the decomposition of methyl linoleate hydroperoxides (MLHP) catalyzed by Co2+ and Cu2+ was studied in a model system using proton nuclear magnetic resonance (NMR) spectroscopy. MLHP were prepared by photoxidation and purified by chromatographic methods. Proton NMR spectroscopy was used to measure reaction rates by monitoring changes in the intensity of the OOH signal. The rate constant of the reaction was obtained by plotting the natural logarithm of MLHP concentration vs time. In the first part of the study, no transition metals were added to the model system, so that the effect of water could be attributed to the interaction between water and MLHP only. The rate constant of the reaction (K) was found inversely proportional to the concentration of water. There was a downfield chemical shift of both hydroperoxide and water peaks in the NMR spectra when water was added. As temperature increased to 40 degrees C, the difference in K between the systems with 0% and 2% water disappeared. It is proposed that the hydroperoxides were solvated with water which retarded their decomposition. When Co2+ was added to the model system, K decreased as the concentration of water increased from 0% to 1.5%. As temperature increased from 18 degrees C to 40 degrees C, differences between the K for 0% and 2% water disappeared. A similar phenomenon was observed in reactions catalyzed with Cu2+. These findings would support a mechanism in which the protective effect of water involves both the solvation of OOH and hydration of the metal catalyst.


Bio-clinical prevalence or non-prevalence of drug addiction over psychiatric symptomatology.

It has been found that opiate abusers once detoxified are afflicted with personality disorders. An attempt was made to test the origin of drug abuse by comparing a group of drug abusers with personality disorders diagnosed as borderline or schizotypal with a group of people suffering from similar personality disorders but who did not use drugs. The results of the test are discussed.


Cyanide dermatosis or a post-mortem artefact?--A case report.

A case of a chronic alcoholic, found dead in the afternoon after consuming an intoxicant early in the morning and showing post-mortem skin slippage with a blackened charred-like appearance, is reported. Viscera chemical analysis gave a positive test for significant quantities of cyanide. However, on histopathological examination, since no evidence of blister formation or vital reaction in the skin tissues were found, this was thought to be a very short duration, accelerated postmortem change phenomenon, due to local heating from contact with the sun-baked terrace.


Confidentiality in clinical psychiatry.

A brief history of the central role of confidentiality in the doctor-patient relationship is presented. Emphasis is placed on the positions of the American Medical Association and World Medical Association. The dilemma posed by the requirement of balancing the rights of the patient against those of society is portrayed. Particular attention is paid to the role of technology and mass society in exacerbating this tension, and the differences between the rights of confidentiality and those of privilege are offered. Recent court cases are cited to illustrate five legal theories to which a patient can resort in alleging damages for the inappropriate disclosure of confidences, as are others in an effort to show the directions in which American courts are heading. Several suggestions are offered to the clinician in dealing with confidentiality.