PAF formation by H2O2-stimulated perfused canine carotid arteries

Perfusion of noncytotoxic concentrations of hydrogen peroxide (H2O2) through canine carotid arteries potentiates neutrophil adhesion to vessel endothelium. Platelet-activating factor (PAF) receptor antagonists block neutrophil adhesion to vessels pretreated with low millimolar concentrations of H2O2. We have used a specific gas chromatographic-mass spectrometric (GC-MS) assay for PAF and applied this to studies of canine carotid arteries perfused with H2O2. Vessels perfused with 1 and 10 mM H2O2 for 20 min produced PAF in a dose-dependent manner, 331 +/- 67 pg/g tissue with 1 mM H2O2 and 1160 +/- 194 pg/g with 10 mM. Vessels that had been denuded of endothelium with a balloon catheter prior to H2O2 perfusion produced similar quantities of PAF in response to H2O2 (220 +/- 72 pg/g and 960 +/- 210 pg/g with 1 and 10 mM, respectively). Cultured canine jugular venous endothelial cells produced PAF in response to 10 mM H2O2 (809 +/- 117 pg/10(7) cells) but carotid arterial smooth muscle cells did not. These results suggest that vascular cells other than endothelial cells may produce PAF following H2O2 perfusion of canine carotid arteries.

Cytotoxicity of oxidized LDL to porcine aortic smooth muscle cells is associated with the oxysterols 7-ketocholesterol and 7-hydroxycholesterol

The cytotoxicity of oxidized low-density lipoprotein (Ox-LDL) to arterial smooth muscle cells (SMCs) may contribute to atherogenesis by causing cell death in core regions of plaques. The aim of the present study was to identify the components of copper-oxidized LDL responsible for its toxicity to porcine aortic SMCs. Toxicity to SMCs was assessed as the decrease in viable cell counts after 3-day cell incubation. Extracts of LDL were tested for toxicity at concentrations equivalent to that derived from 100 micrograms LDL protein per milliliter. Lipid extracts of Ox-LDL but not native-LDL were toxic to SMCs. When separated into neutral and polar lipid classes, only the neutral lipids were toxic (89.7 +/- 0.7% cell loss). The neutral lipids were fractionated further by use of solid-phase extraction and high-performance liquid chromatography (HPLC). Two toxic fractions, causing 93.3% and 60.3% cell loss, were isolated from HPLC and analyzed by gas chromatography/mass spectrometry. The most toxic of these fractions contained 7-ketocholesterol, and the other contained 7 alpha- and 7 beta-hydroxycholesterol. Quantification of these unesterified oxysterols in LDL extracts and comparison with the toxicity of authentic standards indicate that 7-ketocholesterol and 7-hydroxycholesterol are present in Ox-LDL at levels sufficient to account for its toxicity to SMCs.

Rapid assay of iopanoic acid in dog plasma using a Hisep column

A rapid method for the determination of iopanoic acid (IOP) in dog plasma utilizing a Hisep column was developed. A mobile phase of 12% methanol, 88% 0.05 M phosphate buffer pH 3.4 yielded a k' of 8.5 with no interference from proteins present in plasma. Recoveries of IOP from spiked plasma ranged from 97% to 103% at 270 mumol/L and 1.75 mmol/L respectively. Replication was +/- 2.8% at 1.75 mmol/L and +/- 6% at 21 mumol/L. A method utilizing 2,4,6-triiodobenzoic acid as internal standard was also developed for comparison.

Chemical assay of glutaraldehyde incorporation into pericardial tissue

This paper describes the development of a chemical assay to determine the incorporation of glutaraldehyde into pericardial tissue. The procedure is based upon the hydrolysis of the Schiff's bases formed between the glutaraldehyde and the E-amino groups of lysine, the liberated glutaraldehyde being determined as its 2,4-dinitrophenyl-hydrazone by high performance liquid chromatography (HPLC). The HPLC system uses a reverse phase column eluted with a gradient of aqueous acetonitrile (from 60%-70% over 30 minutes). The glutaraldehyde 2,4-dinitrophenylhydrazone is detected at 356 nm. The results show that the assay has sufficient sensitivity (minimum detectable limit 20 pmol of glutaraldehyde 2,4-dinitrophenyl-hydrazone) and reproducibility (+/- 9% at 100 pmol +/- 4% at 1 nmol) to estimate glutaraldehyde incorporation into pericardial tissue. A series of subsequent experiments have documented that temperature and buffer pH are the main determinants affecting glutaraldehyde incorporation into pericardial tissue. Immersion of pericardial tissue in glutaraldehyde solution of pH 9 and 37 degrees C yields an approximately six times greater incorporation than can be achieved if the reaction is performed at 0 degrees C. Further study is underway to relate the amount of Schiff's base bound to that of total incorporated glutaraldehyde.

Glutaraldehyde, gamma-carboxyglutamic acid and calcium in explanted bioprosthetic heart valves

This paper describes the determination of glutaraldehyde, gamma-carboxylglutamic acid (gamma-CGA) and calcium concentrations in nine bioprosthetic heart valves after explantation. The glutaraldehyde and gamma-CGA were determined by high performance liquid chromatography (HPLC) procedures and the calcium by atomic absorption spectrometry. Glutaraldehyde was detectable in only two of these valves at levels of 17% and 2% of that present in an unimplanted valve. The results indicate that there is no correlation between gamma-CGA and calcium deposition, indicating that the gamma-CGA is probably absorbed onto the forming calcium deposit from the circulation and does not contribute to the calcification process, and that the acid hydrolysable glutaraldehyde decreases with time during implantation. There is, however, no correlation between the duration of implantation and the decrease in glutaraldehyde concentration.

Lack of variation in the nucleotide sequence corresponding to the transmembrane domain of the beta-amyloid precursor protein in Alzheimer's disease

The nucleotide sequence corresponding to the APP transmembrane domain and flanking regions of charged amino acids was determined for 91 patients with histologically confirmed Alzheimer's disease, 9 patients with dementias of other etiologies, and 14 controls who had no identifiable brain disease. Twenty-eight of the AD patients had a first-degree relative with dementia. No mutations were detected among the 100 demented patients. However, one of the 14 controls exhibited a change in the 3' base of codon 716 which would not be expected to result in an amino acid substitution at this position.

The role of biological response modifiers in disease control

Immune responses to infectious agents involve a complex set of interactions between cells and the factors they produce that culminate with disease resolution or death. Therefore, the manipulation of the immune system may have a great impact on the preservation and restoration of animal health. Biological response modifiers are agents that modify the host's response to pathogens with resultant beneficial prophylactic or therapeutic effects. The best known example of biological response modifiers are vaccines, by which administration of a nonpathogenic form of a microorganism prepares the immune system to produce a more effective response upon subsequent infection with the pathogenic form. Nevertheless, the use of biological response modifiers other than vaccines that enhance the immune response is now the focus of many investigations. In this review, a brief overview of the immune system is presented, and special emphasis is placed on possible areas of intervention with biological response modifiers and a description of the prophylactic and therapeutic potential of biological response modifiers. Specific examples are presented to demonstrate examples of disease modification by biological response modifiers through stimulation of nonspecific and antigen specific immunities.

Effects of S9977 on adrenergic neurotransmission

1. Experiments were designed to determine whether or not the putative promnesic drug S9977 (1,3,7-trimethyl 8-[3-(4-diethylaminocarbonyl-1-piperazinyl) 1-propyl]-3,7-dihydro (1H)2,6-purinedione hydrochloride) affects peripheral adrenergic neurotransmission. 2. Rings of canine saphenous veins (without endothelium) were suspended for isometric tension recording in conventional organ chambers filled with modified Krebs-Ringer bicarbonate solution. The adrenergic nerve endings were activated with electrical impulses (9 V, 2 msec, 0.25-8 Hz). 3. At 10(-5) M, S9977 significantly reduced the contraction to 0.25, 0.5 and 1 Hz. The compound did not affect the response to higher stimulation frequencies or to exogenous noradrenaline. The inhibitory effect of S9977 was prevented by methiothepin, and not affected by atropine or 8-phenyltheophylline. 4. Helical strips of canine saphenous veins were incubated with [3H]noradrenaline and suspended for superfusion and isometric tension recording. Under basal conditions, S9977 (10(-4) M) augmented, the total 3H-overflow which was due mainly to an augmented overflow of [3H]deoxyphenylglycol (DOPEG); the extraneuronal metabolites 3,4-dihydromandelic acid (DOMA) and 3-methoxy-4-hydroxymandelic acid (VMA) were reduced. 5. During electrical stimulation of the adrenergic nerves, S9977 (10(-4) M) augmented the total 3H-overflow but reduced the contractile response; the evoked overflow of [3H]noradrenaline was not significantly affected. 6. These experiments suggest that S9977 causes the displacement of noradrenaline from the adrenergic varicosities; most of the displaced transmitter is metabolized by intraneuronal monoamine oxidase before reaching the junctional cleft. In addition, S9977 exerts an inhibitory effect on the extraneuronal metabolism of catecholamines. S9977 does not inhibit the exocytotic release of the adrenergic neurotransmitter.

Importance of mild hyperoxaluria in the pathogenesis of urolithiasis--new evidence from studies in the Arabian peninsula

The hypothesis that mild hyperoxaluria is more important than hypercalciuria in the pathogenesis of urolithiasis is re-examined in the light of new evidence. Small increments in urinary oxalate in the normal to high-normal range are much more critical than similar rises in urinary calcium for increasing the relative supersaturation of urine with respect to calcium oxalate, the oxalate/calcium ratio in urine, the total volume of calcium oxalate crystals excreted, the proportion of abnormally large crystals and aggregates of calcium oxalate and the severity of the disorder as defined by the recurrence rate of stone-formation. Data from the Arabian Peninsula, where the prevalence of calcium-containing stones is considerably higher than in the West, have shown that this occurs in spite of the almost complete absence of hypercalciuria. On the other hand, there is a strong association between stone-formation and the occurrence of mild hyperoxaluria. The life-time expectancy of stone-formation in men from various countries is strongly correlated with the average daily excretion of oxalate in the urine of the normal men in these countries. This relationship extends to include patients with enteric and hereditary hyperoxaluria. There is no such relationship, however, between the life-time expectancy of stones and urinary calcium excretion in the same populations. Studies on the regulation of urinary oxalate indicate that it is largely controlled by the quantity of "free" dietary oxalate available for absorption in the lower intestine. This can be calculated from the intakes of calcium and oxalate and the urinary excretion of calcium.

Two cases of coloboma associated with unbalanced translocations

Two cases of coloboma are recorded, both secondary to previously unreported unbalanced translocations. These cases underline the association of chromosomal abnormalities and coloboma, particularly when accompanied by systemic abnormalities. They also highlight the importance of a full systemic assessment of coloboma patients and adequate genetic counselling for both patients and their families.

Effects of S14001 on adrenergic neuroeffector interaction in isolated canine saphenous veins

1. The effects of (S) fluoro-6 (morpholinyl-2 methoxy)-8-tetrahydro-1,2,3,4 quinoleine (S14001) on adrenergic neurotransmission in isolated canine saphenous veins were investigated in experiments which measured the accumulation, overflow and metabolism of 3H-norepinephrine. 2. S14001 inhibited the accumulation of total tritium (3H-norepinephrine and 3H-metabolites of norepinephrine) in a concentration-dependent manner. 3. Under basal conditions, S14001 increased tension and basal effiux of total tritium; the latter consisted predominantly of 3H-DOPEG. The increases in these parameters were not inhibited by desmethylimipramine (DMI). 4. During electrical stimulation, S14001 increased the contraction and overflow of total tritium; the latter consisted predominantly of 3H-DOPEG. The increases in these parameters were inhibited by DMI. 5. These experiments suggest that S14001 has dual effects on adrenergic neurotransmission in the canine saphenous vein: (a) an inhibitory action on the neuronal accumulation; and (b) a pharmacological displacement of the transmitter from adrenergic nerve terminals.

Inter-relation between measurement of serum prostatic specific antigen and transrectal ultrasound in the diagnosis of benign prostatic hyperplasia and prostatic cancer

Serum prostatic specific antigen (PSA) and ultrasound-determined prostatic volume (UPV) were measured in 50 patients with histologically proven benign prostatic hyperplasia (BPH) and in 40 patients with histologically proven prostatic cancer of whom 17 had evidence of distant metastases (M1) and 23 did not (M0). A good correlation between log PSA and UPV was demonstrated in the BPH group and rearrangement of the linear regression equation allowed calculation of a single variable--the log PSA corrected to a standard prostate volume for any given individual. A volume-corrected PSA correctly identified all patients with M1 disease and greatly improved but did not eliminate overlap of M0 disease with BPH. Reduction of serum PSA to a single volume-corrected variable will allow the introduction of practical and optimum protocols for the management of patients with prostatic enlargement.

Response of 6-pyruvoyl-tetrahydropterin synthase deficiency to tetrahydrobiopterin

We have given tetrahydrobiopterin (BH4) in doses ranging from 2.5 to 20 mg/kg/day, each for a duration of 5 days to three patients with 6-pyruvoyltetrahydropterin synthase deficiency. As small a dose as 2.5 mg/kg/day BH4 reduced the blood phenylalanine to normal levels. However, the required dose of BH4 to reduce neopterin and to increase urine biopterin was 5 to 10 mg/kg/day, while 20 mg/kg/day was required for biopterin to appear in cerebrospinal fluid. The results suggest that BH4 effectively reduces endogenous neopterin synthesis. The dose of BH4 needed to normalize liver phenylalanine hydroxylase is one eighth to one fourth that required for normal neurotransmitter metabolism in the central nervous system.

Ultrasonographic dating of pregnancy causes significant errors in Down syndrome risk assessment that may be minimized by use of biparietal diameter—based means

OBJECTIVES

Gestational dates assessed by ultrasonographic measurement of fetal dimensions are usually quoted in terms of complete weeks because the uncertainty of ultrasonographic measurement is approximately +/- 7 days. This study examines the effect of ultrasonographic dating on Down syndrome risk assessment.

STUDY DESIGN

The effect of small changes in measured biparietal diameter resulting in a change in estimated gestational week and the benefits of a more precise measure of fetal gestational age (raw biparietal diameter) are examined mathematically.

RESULTS

If maternal serum alpha-fetoprotein and human chorionic gonadotropin are used to assess Down syndrome risk, risks assessed with ultrasonographically determined dates may be less than or equal to 45% too high for fetuses with biparietal diameter at the lowest end of the size band and less than or equal to 22% too low with biparietal diameter at the top of the size band. If the results for maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol are used, these figures become less than or equal to 150% and less than or equal to 60%, respectively.

CONCLUSION

If ultrasonography is used to assess gestational age, the raw biparietal diameter and not the estimated week of gestation must be used to derive means for calculation of multiples of the mean.

Role of leukotriene B4 in the pathogenesis of hepatic ischemia-reperfusion injury in the rat

A common feature to most models of ischemia-reperfusion injury is the accumulation of polymorphonuclear leukocytes (PMNs) into the post-ischemic tissue during the reperfusion period. Interventions that lead to decreased PMN infiltration protect against tissue injury and therefore a knowledge of the chemotactic mediators leading to PMN accumulation is essential to understanding the pathogenesis of the injury and to the development of successful therapeutic strategies. Leukotriene B4 (LTB4), a metabolite formed via the 5-lipoxygenase pathway from arachidonic acid, is one of the most potent chemotactic mediators known. We have investigated the formation of LTB4 in a well characterized model of hepatic ischemia-reperfusion injury in the rat and made use of a specific leukotriene biosynthesis inhibitor, L663,536, to determine the importance of LTB4 in the pathogenesis of the injury. LTB4 concentrations were measured with a specific and sensitive gas chromatographic-mass spectrometric method previously developed in our laboratory. In liver tissue LTB4 levels were below the detection limit of 20 pg/g before 45 min ischemia and did not increase during the first 6 h of reperfusion. However, at 15 h and 24 h reperfusion LTB4 concentrations had increased to levels 50-fold those in control liver (867 +/- 267 pg/g). The increase of plasma alanine aminotransferase (ALT) activities indicated two phases of injury, an initial phase during the first few hours of reperfusion, and a second more severe injury phase between 6 h and 24 h reperfusion. PMNs accumulated in tissue throughout the reflow period reaching 700 +/- 49 per 50 high power fields (HPF) at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume of normal prostate, of prostate cancer, and of benign prostatic hyperplasia: are correlations with prostate specific antigen clinically useful?

This retrospective study correlated prostate volume, determined by transrectal ultrasonography, with serum prostate specific antigen (PSA), by Deming regression analysis, in patients with confirmed benign prostatic hyperplasia (BPH) and patients with non-metastatic (M0) or metastatic (M1) prostate cancer. In BPH, a highly significant correlation was found between log10[PSA] and prostate volume. When this PSA/volume regression pattern for BPH was used as a reference standard, all 17 patients with M1 prostate cancer and 83% of the 23 patients with M0 disease were discriminated from BPH.

Pathological changes in bovine mammary glands following intramammary infusion of recombinant interleukin-2

Eighteen lactating dairy cows were used to evaluate the physiological response of mammary glands to increasing doses of recombinant bovine interleukin-2. Right front and rear quarters were intramammarily infused with five different doses (.1 to 100 micrograms per quarter) of interleukin-2 as either a single or multiple treatment. Left front and rear quarters were intramammarily infused with a saline placebo and served as within-animal controls. Milk secretion samples for compositional analysis were collected from each quarter prior to infusion and at 12, 24, 36, and 48 h following infusion. Animals were slaughtered by exsanguination immediately following the 48-h sampling period, and mammary gland tissue was obtained for morphometric analysis. No changes in milk composition were observed between control quarters and those infused with up to 10 micrograms of interleukin-2 per quarter, administered as either a single or multiple treatment. Quarters infused with a single 100-micrograms dose of interleukin-2 or three consecutive doses of 25 and 100 micrograms of interleukin-2 had significantly lower lactose concentrations; there was a concomitant increase in bovine serum albumin, pH, and SCC compared with preinfusion concentrations or with control quarters. Morphometric analysis of tissue demonstrated an increase in stroma, a decrease in lumenal area, and a marked increase in the number of infiltrating leukocytes in those quarters infused with the higher doses of interleukin-2. Results suggest that interleukin-2 can be intrammammarily infused at doses as high as 10 micrograms per quarter without adversely affecting milk quality or normal mammary gland function.

The effect of weight correction on risk calculations for Down's syndrome screening

Recent advances in prenatal screening have led to the possibility that the risk of Down's syndrome associated pregnancy may be assessed by blood tests for maternal serum alphafetoprotein, human chorionic gonadotrophin (and possibly unconjugated oestriol) taken at 15-18 weeks of gestation. In neural tube defect screening correction of maternal serum alphafetoprotein for maternal weight has been recommended, although the precise method for weight correction is still under debate. We report an assessment of weight correction for maternal serum alphafetoprotein and human chorionic gonadotrophin based on 1408 singleton pregnancies and for unconjugated oestriol based on 197 singleton pregnancies. We demonstrate that weight correction of maternal serum alphafetoprotein and human chorionic gonadotrophin is statistically valid but that correction of unconjugated oestriol is not.

Biopterin-dependent hyperphenylalaninemia due to deficiency of 6-pyruvoyl tetrahydropterin synthase

We describe the clinical, neurologic, and biochemical findings in 10 patients with 6-pyruvoyl tetrahydropterin synthase (6-PTS) deficiency from seven families, all of whom originate from one large tribe in Saudi Arabia. This deficiency presents with severe, early onset of failure to thrive, neurologic deterioration, and morbidity and mortality secondary to repeated episodes of bronchopneumonia or cardiorespiratory abnormalities. The urinary pterin excretion pattern indicates deficient activity of 6-PTS, which has been confirmed by direct enzyme assay in red blood cells of three patients. We treated our patients with combined use of tetrahydrobiopterin 20 mg/kg/d, L-dihydroxyphenylalanine 15 mg/kg/d, carbidopa 3.75 mg/kg/d, and L-5-hydroxytryptophan 5 mg/kg/d. Neurologic findings improved significantly in all after 5 to 24 months. Although head circumference and weight returned to the lower limit of normal in four, height normalized only in one of seven patients. Despite an unrestricted diet during combined therapy, blood phenylalanine and urinary excretion of neopterin and biopterin returned to normal.

The uptake of oestrone from the lumen of the isolated perfused rat gut

1. In the isolated perfused rat gut oestrone was not taken up from the perfusate but was rapidly taken up from the gut lumen when administered in dimethyl sulphoxide or in 10% acetone in water. 2. Uptake from corn oil was much slower and the rate was concentration-dependent. 3. When given in dimethyl sulphoxide or in aqueous acetone, the residual oestrone in the gut lumen was largely unchanged, with only about 10% being present as the glucuronide. Of the oestrone in the gut perfusate, some 40% was glucuronidated. 4. No evidence was obtained for any reduction or hydroxylation, or for any sulphation, during uptake of oestrone by the gut. 5. No secretion of oestrone or its metabolites into lymph could be detected.

Gas chromatographic-mass spectrometric analysis of lipoxygenase products in post-ischemic rabbit myocardium

Leukotriene B4 (LTB4) is a potent chemotactic compound for neutrophils and is thought to be an important mediator of myocardial ischemia-reflow injury. We have measured LTB4 in rabbit cardiac tissue following ischemia-reflow using a sensitive and specific gas chromatographic-mass spectrometric (GC-MS) assay. The concentration of LTB4 in rabbit myocardium following 45 min ischemia and 3 h reflow was 48.7 +/- 12.5 pg/g, significantly higher than in non-ischemic tissue from the same animal (17.5 +/- 3.9 pg/g). These concentrations were at least an order of magnitude lower than previously reported values assessed by radioimmunoassay (RIA). Compared with the GC-MS method, RIA greatly overestimated LTB4 concentrations in cardiac tissue. The capacity of post-ischemic myocardium to produce lipoxygenase products, LTB4, 5-, 12- and 15-HETEs was also assessed following incubation of myocardium ex vivo with calcium ionophore. In all animals ischemic cardiac tissue produced greater amounts of LTB4, 5-, and 12-HETEs than non-ischemic myocardium and 12-HETE was the major product. Neutrophils that have accumulated in the injured tissue may be a major source of these products. However, in contrast to cardiac tissue, isolated rabbit neutrophils stimulated with A23187 produced 5-HETE as the major product with very little 12-HETE formed. These latter findings suggest that cells other than neutrophils may contribute to the production of lipoxygenase products during myocardial ischemia-reflow injury.

Lipid hydroperoxy and hydroxy derivatives in copper-catalyzed oxidation of low density lipoprotein

Oxidation of low density lipoprotein (LDL) causes changes in the biological properties of LDL that may be important in atherogenesis. That LDL oxidation is accompanied by lipid peroxidation has been demonstrated, but previous analyses of the products of LDL oxidation have not included measurement of specific lipid hydroperoxy and hydroxy derivatives. In this study, LDL was isolated from plasma of normal volunteers and exposed to oxygenated buffer and 5 microM CuSO4 for 24 h. Oxidized LDL showed decreased linoleate (18:2) and arachidonate (20:4) content with increased concentrations of thiobarbituric acid reactive substances (TBARS) and hydroxy and hydroperoxy 18:2 and 20:4. The electrophoretic mobility of the LDL protein also was increased by oxidation. After reduction, the hydroxy fatty acids were characterized by gas chromatography-mass spectrometric analysis of the trimethylsilyl ether methyl ester derivatives. The hydroperoxy and hydroxy derivatives accounted for approximately 70% of the linoleate consumed during LDL oxidation and represented 45-fold more product than was measured by TBARS analysis. Numerous biological properties, including cytotoxic and chemoattractant activities of hydroperoxy and hydroxy fatty acids, have been reported, but the manner in which they may contribute to atherogenesis requires further study.

Haiti. Educating factory workers

There are approximately 50,000 workers employed in the light assembly industry in Haiti. About 70% are women, the majority of whom are aged between 25 and 34 years, and are either single or in a nonpermanent relationship with the father of their children. Many live and work in appalling conditions, surviving on very low wages to support several children and an extended family. The acquired immunodeficiency syndrome (AIDS) is now a visible problem in many factories. In October 1988, the Center for the Promotion of Women Workers (Centre de Promotion des Femmes Ouvriers/CPFO) launched a pilot AIDS education program for factory women. The Center, based in a large industrial zone near the airport, runs a health clinic and courses in literacy, communications skills, health promotion and family planning. The new AIDS program allowed CPFO staff to gain entry into factories for the 1st time. Other courses were held outside working hours and outside factory premises. Staff contacted manages by telephone to arrange a meeting to discuss AIDS and to ask permission to hold educational "round tables" with workers. Of 18 managers in the factories approached over a 12-month period, only 2 refused entry to CPFO staff. Almost all managers reported they had registered between 2 and 5 deaths from AIDS among their employees over the past couple of years. A total of 85 educational sessions, each lasting about 2 hours, were held within 28 different factories, community or labor organizations reaching 3063 workers (male and female). In each session, the presentation was carried out by 2 CPFO trained monitors and included a slide show, flip charts, and the video "Met ko," originally produced for Haitian immigrants in New York. The most important aspect of the program was the training of 38 volunteer factory-based health promoters. These promoters attended the round table sessions, where they facilitated discussion and distributed condoms and were subsequently available for counseling co-workers. Initially, the Center intended to recruit only literate women as promoters, but several nonliterate women were selected for training by labor organizations 18 hours of tuition and discussion of AIDS/human immunodeficiency virus were held over 2 1/2 weeks, including sessions on group dynamics and organizational skills. To improve communications skills, sessions included role play exercises which were videotaped and played back to trainees. Training in communication skills also helps promoters participate in activities aimed at supporting a broader range of workers' rights.

Comparison of antioxidant and nonantioxidant lipoxygenase inhibitors on neutrophil function. Implications for pathogenesis of myocardial reperfusion injury

The activation and accumulation of leukocytes during inflammatory processes such as that initiated by myocardial ischemia and reflow appear to be major determinants of irreversible tissue injury. Myocardial salvage by dual cyclooxygenase/lipoxygenase inhibitors and selective 5-lipoxygenase inhibitors has suggested a role for lipoxygenase (LOX) products, such as the potent chemotactic factor leukotriene B4, in ischemia-reflow injury. However, many LOX inhibitors are antioxidants and several have been shown to directly inhibit neutrophil function in vitro, thereby questioning the role of LOX products in reperfusion injury. To clarify further the protective mechanism of lipoxygenase inhibitors, we have examined the effects of two nonantioxidant inhibitors, SK&F 86002 and REV-5901, on human neutrophil activation and function in vitro. The antioxidant LOX inhibitor nordihydroguiaretic acid, which served as a positive control, exhibited a concentration-dependent inhibition of N-formyl-methionyl-leucyl-phenylalanine (fMLP) and recombinant C5a-induced neutrophil bipolarization, fMLP-induced upregulation of the adherence glycoprotein Mac-1 (CD11b/CD18), fMLP-induced aggregation and neutrophil adherence to and migration through interleukin-1-stimulated human endothelial monolayers. In contrast, neither SK&F 86002 nor REV-5901 (in concentrations up to 50 microM) had any effect on these functions, nor did they inhibit neutrophil oxidative metabolism (phorbol myristate acetate-induced chemiluminescence). Inasmuch as both of these agents have been observed to reduce myocardial ischemia-reflow injury in vivo, their failure to directly inhibit neutrophil function further supports an important role for chemotactic LOX products in the pathogenesis of reperfusion injury.

A study of the vaginal contraceptive sponge used with and without the fertility awareness method

The actual effectiveness rates of natural and barrier methods of family planning are lower than the theoretical ones. If couples accurately defined the limits of the fertile phase and used barriers at that time, then actual effectiveness might increase. A randomized, controlled clinical trial was initiated to determine the effectiveness of the contraceptive sponge used only during the fertile time and to compare this with sponge use at every intercourse. Recruitment problems and discontinuation forced the early termination of this study, but qualitative information about compliance and acceptability was collected. Common sponge problems were reported as were misuses of the sponge, but problems and misuse were not related. Determination of the fertile phase was reportedly easy, but complaints of and discontinuation for inconvenience occurred. For unplanned pregnancies, contraceptive behaviors around the time of conception are presented.

Glutathione disulfide formation and lipid peroxidation during cardiac ischemia and reflow in the dog in vivo

The content of glutathione disulfide (GSSG) in tissue, coronary sinus blood plasma, and in cardiac lymph was measured in a well-characterized model of regional cardiac ischemia and reflow in dogs in vivo in order to assess the magnitude of the oxidant stress produced. No increase in GSSG content was observed during 60 min of occlusion of the circumflex or left anterior descending arteries, or during up to 70 min of reflow. The contents of 11-, 12-, and 15-hydroxyeicosatetraenoates (HETEs) in total lipids also were not increased following 60 min of regional ischemia and up to 60 min of reflow. In addition, global ischemia produced by aortic crossclamping and cardiopulmonary bypass did not increase HETE content. In contrast, infusion of tertiary butyl hydroperoxide (tBHP) into the left atrium produced readily measurable increases in GSSG content with or without prior induction of myocardial ischemia. Infusion of tBHP also increased tissue contents of the HETEs. These findings indicate that the canine myocardium subjected to ischemia-reflow conditions does not generate large amounts of reactive oxygen and does not form significant amounts lipid peroxidation products.

Quantitation of leukotriene B4 in human serum by negative ion gas chromatography-mass spectrometry

Leukotriene B4 (LTB4) is a potent chemotactic agent formed via the 5-lipoxygenase pathway from arachidonic acid. To understand the role LTB4 plays in several pathological processes it is essential that endogenous concentrations of LTB4 be accurately quantitated. We have developed a method based on electron capture negative ion mass spectrometry for the analysis of LTB4 in serum at low picogram per milliliter concentrations. Blood is collected into the 5-lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) to suppress ex vivo formation. Serum is isolated, equilibrated with the internal standard [2H4]LTB4, and extracted using octadecyl-silica (C-18) cartridges. After conversion of the carboxylic acids to their pentafluorobenzyl esters the extract is purified by straight-phase HPLC. Gas chromatographic-mass spectrometric analysis is accomplished on the tert-butyldimethylsilyl ether derivatives using dual-selected ion monitoring of m/z 431 and 435. These ions correspond to loss of tert-butyldimethylsilanol from the (M-PFB)- ion of endogenous and [2H4]LTB4, respectively. The concentration of LTB4 in human serum samples was 10.0 +/- 4.0 pg/ml (n = 5). The assay exhibited satisfactory precision, with an intraassay coefficient of variation of 17% and a high degree of accuracy. The concentration of LTB4 in serum collected with (NDGA) was less than 10% of that observed in blood collected without the lipoxygenase inhibitor. Ex vivo formation can therefore be a major obstacle in assessing circulating levels of LTB4.

Selected reaction monitoring during gas chromatography/mass spectrometry of eicosanoids

Gas chromatography/electron capture negative ion mass spectrometry of eicosanoids, as pentafluorobenzyl (PFB) ester, methyl oxime (where applicable), trimethylsilyl (TMS) ether derivatives, is reported using a double-focusing instrument of trisector configuration. Sub-picogram detection limits were observed for prostaglandins E1, E2 and F2 alpha during selected ion monitoring (SIM) of [M-PFB]- ions. Selected reaction monitoring (SRM) of [M-PFB]-----[M-PFB-TMSOH]-, occurring in the first field-free region, was of modest sensitivity, reflecting the stability of the [M-PFB]- ions. The leukotriene B4 (LTB4) derivative was successfully analyzed by SIM at the low-picogram level. In this instance, the fragmentation [M-PFB]-----[M-PFB-TMSOH] occurred in high yield in the first field-free region. The advantageous improvement in selectivity of detection that may be achieved with SRM was evident during the analysis of a serum extract for LTB4.

Liver membrane calcium transport in diquat-induced oxidative stress in vivo

Hepatic necrosis is produced rapidly by 0.1 mmol/kg diquat in male Fischer-344 rats but not Sprague-Dawley rats, yet massive oxidant stress is caused by diquat in both strains of rat. Liver plasma membrane calcium uptake was unaltered by diquat treatment in either strain. However, diquat inhibited ATP-dependent calcium sequestration by hepatic microsomes from Fischer rats by 33% (33 +/- 2 versus 50 +/- 2 nmol/mg/20 min), whereas liver microsomal calcium uptake in Sprague-Dawley rats was not decreased by diquat treatment. Microsomes of diquat-treated Fischer rats showed marked increases in calcium efflux versus controls (k efflux = 0.115 +/- 0.027 versus 0.051 +/- 0.005 min-1; p less than 0.025), but microsomes of diquat-treated Sprague-Dawley rats exhibited no significant change in efflux rate. Calcium uptake by the endoplasmic reticulum of saponin-permeabilized isolated hepatocytes was diminished in parallel with diquat cytotoxicity. Significant increases in 11-, 12-, and 15-hydroxy 20:4 fatty acids were found in liver microsomes isolated after diquat treatment in vivo and administration of desferrioxamine (0.24 mmol/kg, intraperitoneally) administered before diquat significantly protected against the inhibition of microsomal calcium uptake. These data suggest a possible role for Fenton chemistry and lipid peroxidation in this feature of diquat-generated hepatic damage in vivo.

Alkylation of the liver plasma membrane and inhibition of the Ca2+ ATPase by acetaminophen

Acetaminophen is activated metabolically to yield reactive species that bind covalently to liver cell macromolecules. The extent of covalent binding correlates with the occurrence and severity of hepatic necrosis. We reported previously [J. O. Tsokos-Kuhn, E. L. Todd, J. B. McMillin-Wood and J. R. Mitchell, Molec. Pharmac. 28, 56 (1985)] that active Ca2+ accumulation of isolated liver plasma membranes is decreased 60-75% after a hepatotoxic dose of acetaminophen in vivo. We now report that the protein of isolated liver plasma membranes was substantially labeled with drug metabolites after administration of [3H]acetaminophen. There was no increase in passive membrane permeability that might cause diminished Ca2+ accumulation. Intravesicular volume and relative purity of the vesicle preparations after acetaminophen were not different from controls. However, (Ca2+,Mg2+)-ATPase, a possible biochemical expression of the Ca2+ pump, was decreased 31% (P less than 0.025) after acetaminophen treatment. ATPase activity in both control and treated groups was enhanced by isolating membranes in the presence of 5 mM reduced glutathione (GSH), but the effects of drug treatment were not reversed. A similar effect of GSH on Ca2+ accumulation was observed previously [J. O. Tsokos-Kuhn, E. L. Todd, J. B. McMillin-Wood and J. R. Mitchell, Molec. Pharmac. 28, 56 (1985)]. These data are consistent with a hypothesis wherein alkylation of membrane proteins by reactive acetaminophen metabolites is a factor in the onset of hepatic necrosis after acetaminophen. They are not consistent with an oxidative stress hypothesis where thiol S-thiolation of membrane components is postulated to produce altered membrane permeability or thiol-reversible alterations in membrane protein structure and enzymatic function.

Characterization of glutathione conjugates by fast atom bombardment/tandem mass spectrometry

The collisionally activated decomposition of [M + H]+ ions, generated by fast atom bombardment (FAB) of glutathione conjugates, has been studied by tandem mass spectrometry (MS/MS) using hybrid sector/quadrupole instruments. Abundant fragments of diagnostic utility were present in the daughter ion spectra. Common fragmentation modes were observed but their relative importance was strongly dependent on the nature of the conjugated species. As an example of a general approach to the characterization of glutathione conjugates in biological samples, the acetaminophen-glutathione conjugate was identified in rat bile, following coadministration of (2H0)- and (2H3)acetaminophen, using the experimental sequence: (i) conventional FAB mass spectrometric analysis, (ii) MS/MS using constant neutral loss (129 u) scanning to identify parent ions corresponding to glutathione conjugates, (iii) MS/MS to yield daughter ion spectra of parents so identified and corresponding to (2H0)- and (2H3)-labeled conjugates.

Practice effects in backward masking

In two experiments we demonstrate that much larger practice effects occur in a backward masking paradigm where patterned masks are used than in similar visual processing paradigms, such as lateral masking and whole report. In additional experiments we examine four possible explanations for the large practice effects: increased familiarity with the paradigm in general, learning about the targets, learning about the masks, and enhanced sensory processing. Because of failure to observe similar practice effects in related paradigms not involving backward masking and because of the sustained nature of the improvement, we reject the first explanation as a source of practice effect. Experiment 3 allowed us to reject target learning as a source of improvement as well; target sets were switched at the end of training, but no decrement in performance was observed. In Experiment 4, mask sets were switched at the end of training, revealing a significant decrement in performance. Learning about the specific masks, then, does contribute to the observed improvement. However, it is responsible for only about one third of the overall improvement in performance. The final experiment provides evidence that the residual improvement is due to enhanced sensory processing. In that experiment, training on backward masking led to a lowered threshold in a two-flash paradigm but not to a significant change in whole-report performance.

Prenatal diagnosis and perinatal management of frontoethmoidal meningoencephalocele

Frontoethmoidal meningoencephaloceles (FEM) are exceedingly rare in the western hemisphere, Australia, and Europe with an estimated frequency of 1 in 40,000 live births. Among the inhabitants of Thailand, Burma, Malaysia, Indonesia, and parts of the Soviet Union, however, the frequency is as high as 1 in 5000, accounting for 15% of all neural tube defects (NTD). Normal maternal serum alpha-fetoprotein (MSAFP) values usually will be found in these cases since most encephaloceles are closed, skin covered defects. Correct interpretation of the sonographic findings is crucial in establishing a diagnosis as well as giving prognostic and recurrence risk information. To our knowledge, this is the first reported case of prenatally diagnosed FEM. Perinatal management, differential diagnosis for disorders associated with this malformation, and epidemiologic information regarding this rare condition are discussed. It is anticipated that the prenatal sonographic findings may be applied to establish this diagnosis in similarly affected fetuses.

Abnormal carotid arteries in the velocardiofacial syndrome: a report of three cases

Internal carotid arteries of unusual size and tortuosity were found before or at the time of pharyngeal flap surgery in three children who had the velocardiofacial syndrome with velopharyngeal insufficiency. In two cases, medial displacement of the arteries prevented surgery, and in the other, hypernasality persisted because only a narrow, asymmetrical flap could be raised. Medial displacement of the internal carotid arteries inhibits surgical treatment of velopharyngeal insufficiency, necessitating treatment with a prosthetic speech device in such children. Since displacement and tortuosity may be associated findings in the velocardiofacial syndrome, the exact location of the internal carotids should be ascertained when pharyngeal flap surgery is planned.