Combined use of exhaled hydrogen peroxide and nitric oxide in monitoring asthma

Oxidative stress contributes to airway inflammation and exhaled hydrogen peroxide (H2O2) and nitric oxide (NO) are elevated in asthmatic patients. We determined the concentrations of expired H2O2 and NO in 116 asthmatic (72 stable steroid-naive, 30 stable steroid-treated, and 14 severe steroid-treated unstable patients) and in 35 healthy subjects, and studied the relation between exhaled H2O2, NO, FEV1, airway responsiveness, and eosinophils in induced sputum. Both exhaled H2O2 and NO levels were elevated in steroid-naive asthmatic patients compared with normal subjects (0.72 +/- 0.06 versus 0.27 +/- 0.04 microM and 29 +/- 1.9 versus 6.5 +/- 0. 32 ppb, respectively; p < 0.001) and were reduced in stable steroid-treated patients (0.43 +/- 0.08 microM, p < 0.05, and 9.9 +/- 0.97 ppb, p < 0.001). In unstable steroid-treated asthmatics, however, H2O2 levels were increased, but exhaled NO levels were low (0.78 +/- 0.16 microM and 6.7 +/- 1.0 ppb, respectively). There was a correlation between expired H2O2, sputum eosinophils and airway hyperresponsiveness (methacholine PC20). Exhaled NO also correlated with sputum eosinophils, but not with airway hyperresponsiveness. Our findings indicate that measurement of expired H2O2 and NO in asthmatic patients provides complementary data for monitoring of disease activity.

The value of forced expiratory volume in 1 s in screening subjects with stable COPD for PaO2 < 7.3 kPa qualifying for long-term oxygen therapy

Guidelines on the management of chronic obstructive pulmonary disease (COPD) issued by the European Respiratory Society (ERS), British Thoracic Society (BTS), American Thoracic Society (ATS), and Department of Health for England and Wales (DoH) suggest differing values of forced expiratory volume in 1 s (FEV1) below which arterial blood gas analysis should be performed to determine the presence of severe hypoxaemia and possible long-term oxygen therapy (LTOT) requirement. This study aimed to determine the value of FEV1 at these different levels in screening for LTOT requirement defined as PaO2 < 7.3 kPa in subjects with stable COPD. Comparative measures were taken against other lung function tests of volume and diffusing capacity. A retrospective analysis of paired lung function and arterial oxygen measurements in 491 subjects was made. The positive and negative predictive values, sensitivity and specificity of FEV1 < 70% predicted (ERS), FEV1 < 50% predicted (ATS), FEV1 < 40% predicted (BTS) and FEV1 < 1.51 (DoH) were determined for fulfilling LTOT criteria (PaO2 < 7.3 kPa). The correlation between lung function variables and PaO2 was established. Logistic regression analysis was used to classify subjects with PaO2 < 7.3 kPa and PaO2 > or = 7.3 kPa. Using FEV1 to screen for LTOT requirement produced a high negative predictive value at all four suggested limits (FEV1 < 70% 100%, FEV1 < 50% 96%, FEV1 < 40% 95%, FEV1 < 1.51 97%). However, the positive predictive values were low (FEV1 < 70% 13%, FEV1 < 50% 16%, FEV1 < 40% 19%, FEV1 < 1.51 15%) as were sensitivities. No single lung function variable was a strong determinant of PaO2. FEV1 % pred (r = 0.40), FVC % pred (r = 0.34) and TLCO % pred (r = 0.27) had the strongest relationships. Logistic regression also placed FEV1 % pred and TLCO % pred as the best predictors of PaO2 < 7.3 kPa. We conclude no lung function variable correlates well with PaO2 in subjects with stable COPD. The best predictor of PaO2 < 7.3 kPa was FEV1 % pred. Whilst a low FEV1 is a poor predictor of LTOT requirement in an individual, PaO2 < 7.3 kPa is only found in subjects with a low FEV1. A high FEV1 may be used to exclude subjects from further investigation for LTOT and prevent unnecessary arterial sampling.

Treatment of orofacial and ileo-colonic Crohn's disease with total enteral nutrition

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Fatty acid cycling in human hepatoma cells and the effects of troglitazone

Fatty acid cycling by chain shortening/elongation in the peroxisomes is an important source of fatty acids for membrane lipid synthesis. Its role in the homeostasis of nonessential fatty acids is poorly understood. We report here a study on the cycling of saturated fatty acids and the effects of troglitazone in HepG2 cells in culture using [U-13C]stearate or [U-13C]oleate and mass isotopomer analysis. HepG2 cells were grown in the presence of 0.7 mmol/liter [U-13C]stearate or [U-13C]oleate, and in the presence and absence of 50 microM troglitazone for 72 h. Fatty acids extracted from cell pellets after saponification were analyzed by gas chromatography/mass spectrometry. Peroxisomal beta-oxidation of uniformly 13C-labeled stearate (C18:0) and oleate (C18:1) resulted in chain shortening and produced uniformly labeled palmitate (C16:0) and palmitoleate (C16:1). In untreated cells, 16% of C16:0 was derived from C18:0 and 26% of C16:1 from C18:1 by chain shortening. Such contributions were significantly increased by troglitazone to 23.6 and 36.6%, respectively (p < 0.001). Desaturation of stearate contributed 67% of the oleate, while reduction of oleate contributed little to stearate (2%). The desaturation of C18:0 to C18:1 was not affected by troglitazone. Our results demonstrated a high degree of recycling of C18:0 and C18:1 to C16:0 and C16:1 through chain shortening and desaturation. Chain shortening was accompanied by chain elongation in the synthesis of other long chain fatty acids. Troglitazone specifically increased recycling by peroxisomal beta-oxidation of C18 to C16 fatty acids, and the interconversion of long chain fatty acids was associated with reduced de novo lipogenesis.

Increased formation of the potent oxidant peroxynitrite in the airways of asthmatic patients is associated with induction of nitric oxide synthase: effect of inhaled glucocorticoid

Peroxynitrite is a potent oxidant formed by the rapid reaction of the free radicals nitric oxide (NO) and superoxide. It causes airway hyperresponsiveness and airway epithelial damage, enhances inflammatory cell recruitment, and inhibits pulmonary surfactant. Asthma is characterized by increased airway hyperresponsiveness, airway epithelial shedding, and inflammation. We examined the production of peroxynitrite and the expression of inducible nitric oxide synthase (iNOS) in airways of asthmatic patients compared to normal control subjects. We also performed a double-blind, crossover randomized-order, placebo-controlled study on 10 asthmatic patients to study the effects of inhaled glucocorticoid treatment (Budesonide) on the formation of peroxynitrite and NO. Fiberoptic bronchial biopsies were examined by immunohistochemistry with antiserum to nitrotyrosine, a marker of protein nitration by peroxynitrite. We also examined the expression of iNOS by immunohistochemistry and in situ hybridization, and measured exhaled NO by chemiluminescence. We correlated the airway production of peroxynitrite with pulmonary functions and airway responsiveness. In airway passages of control subjects, there was weak or no nitrotyrosine immunoreactivity. In contrast, there was strong immunoreactivity for nitrotyrosine in the airway epithelium and inflammatory cells in the airways of persons with asthma. Budesonide treatment resulted in a significant reduction in nitrotyrosine immunoreactivity. Expression of iNOS was evident in the airway pithelium of controls and asthmatic patients, but was significantly more abundant in asthmatic patients. The presence of nitrotyrosine in the airway epithelium (r=-0.841, P<0.0001; r=-0.771, P=0.0004) and inflammatory cells (r=-0.727, P=0014; r=-0.681, P=0.004) correlated inversely with methacholine PC20 and forced expiratory volume in 1 s, respectively. Asthma is associated with increased peroxynitrite formation in the airways, which is reduced after Budesonide treatment. The potent oxidant peroxynitrite may contribute to airway obstruction and hyperresponsiveness and epithelial damage in asthma.

Calibration of isotope ratio mass spectrometry working standard for 2H/1H ratio analysis

A method is described for the calibration of an isotope ratio mass spectrometry working standard for 2H/1H analysis using highly purified (> 99.99% enriched) deuterium oxide (2H2O). Serial dilution of such a compound can be used to construct a standard curve for calibration purposes using the relationship [formula: see text] where APE is the atom percent excess. It was found that the determined rWR had a precision of +/- 1%. Most of the variation came from sample handling, which includes the serial dilution of the weighed deuterium oxide, the reduction of water to hydrogen gas and the introduction of the hydrogen gas into the mass spectrometer. The use of this calibration procedure allows the direct determination of the isotope ratio rSA, and APE from a standard curve over a wide range of enrichment. Unlike the reference standards V-SMOW and SLAP, the highly purified deuterium oxide is non-exhaustible and readily available. The highly purified deuterium oxide should be used in place of secondary standards to calibrate working references for 2H/1H analysis in biological studies.

Postexposure prophylaxis for human immunodeficiency virus: frequency of initiation and completion of newly recommended regimen

Recent evidence demonstrating the efficacy of zidovudine, as well as experience with protease inhibitors, led to revision of recommendations for occupational exposures to human immunodeficiency virus-infected blood. At our hospital, this resulted in significant increases in rates of reported exposures and prophylaxis initiation. Among 10 healthcare workers given three-drug, protease-inhibitor-containing regimens, five completed 4 weeks, two completed 4 weeks of two drugs, and three stopped due to intolerance. Three workers missed work due to side effects.

Attenuated phase-shifting masks of chromium aluminum oxide

Chromium aluminum oxide was chosen as a new candidate for use as an attenuated phase-shifting mask (Att-PSM) material. The compositions of films were correlated with optical properties. With the measured and the fitted data, we simulated the transmittance and the phase shift using the matrix method. Consequently, we acquired optimum parameters for Att-PSM's, such as Al/Cr = 1.9-2.5 and d = 120 nm at a 193-nm wavelength, Al/Cr = 1.0-1.7 and d = 128 nm at a 248-nm wavelength, and Al/Cr = 0-0.1 and d = 170 nm at a 365-nm wavelength. This simulation was verified by transmittance measurement.

Mass isotopomer study of the nonoxidative pathways of the pentose cycle with [1,2-13C2]glucose

We present a single-tracer method for the study of the pentose phosphate pathway (PPP) using [1,2-13C2]glucose and mass isotopomer analysis. The metabolism of [1,2-13C2]glucose by the glucose-6-phosphate dehydrogenase, transketolase (TK), and transaldolase (TA) reactions results in unique pentose and lactate isotopomers with either one or two 13C substitutions. The distribution of these isotopomers was used to estimate parameters of the PPP using the model of Katz and Rognstad (J. Katz and R. Rognstad. Biochemistry 6: 2227-2247, 1967). Mass and position isotopomers of ribose, and lactate and palmitate (products from triose phosphate) from human hepatoma cells (Hep G2) incubated with 30% enriched [1,2-13C2]glucose were determined using gas chromatography-mass spectrometry. After 24-72 h incubation, 1.9% of lactate molecules in the medium contained one 13C substitution (m1) and 10% contained two 13C substitutions (m2). A similar m1-to-m2 ratio was found in palmitate as expected. Pentose cycle (PC) activity determined from incubation with [1,2-13C2]glucose was 5.73 +/- 0.52% of the glucose flux, which was identical to the value of PC (5.55 +/- 0.73%) determined by separate incubations with [1-13C] and [6-13C]glucose, 13C was found to be distributed in four ribose isotopomers ([1-13C]-, [5-13C]-, [1,2-13C2]-, and [4,5-13C2]ribose). The observed ribose isotopomer distribution was best matched with that provided from simulation by substituting 0.032 for TK and 0.85 for TA activity relative to glucose uptake into the model of Katz and Rognstad. The use of [1,2-13C2]glucose not only permits the determination of PC but also allows estimation of relative rates through the TK and TA reactions.

Increased sensitivity of the cough reflex in progressive systemic sclerosis patients with interstitial lung disease

Cough is a common presenting symptom of interstitial lung disease (ILD). The aim of this study was to examine the cough reflex in patients with progressive systemic sclerosis (PSS), with and without associated ILD. The cough reflex to inhalation of chloride deficient solutions and capsaicin was determined in patients with PSS with associated ILD (n=12), compared to patients with PSS without ILD (n=12). In addition, patients with a chronic dry cough (n=12) and healthy subjects (n=10) without cough were studied. Cough responses to inhalation of isotonic solutions containing 150, 75, 37.5 and 0 mM Cl- ions and of capsaicin (0.9-500 mM) were measured. PSS patients with ILD reported a significantly higher cough score than PSS patients without ILD (p<0.03). ILD patients coughed more than those without ILD to Cl- of 37.5 and 0 mM (19.1+/-5.0 vs 6.2+/-1.9 coughs x min(-1) (p<0.03), and 29.2+/-5.0 vs 14.1/-4.1 coughs x min(-1) (p<0.04), respectively). The log concentration of capsaicin causing two or five coughs was lower in PSS with ILD compared to PSS without ILD (0.74+/-0.15 mM vs 2.12+/-0.26 mM; p<0.002). Patients with chronic dry cough had a similar degree of response to low-chloride and capsaicin solutions as patients with PSS and ILD, whilst healthy controls had a similar degrees of response to PSS patients. There is an increased cough reflex in patients with interstitial lung disease, which may represent sensitization of airway sensory nerves. This may be the basis for the chronic dry cough in patients with interstitial lung disease.

Increased sensitivity of the cough reflex in progressive systemic sclerosis patients with interstitial lung disease

Cough is a common presenting symptom of interstitial lung disease (ILD). The aim of this study was to examine the cough reflex in patients with progressive systemic sclerosis (PSS), with and without associated ILD. The cough reflex to inhalation of chloride deficient solutions and capsaicin was determined in patients with PSS with associated ILD (n=12), compared to patients with PSS without ILD (n=12). In addition, patients with a chronic dry cough (n=12) and healthy subjects (n=10) without cough were studied. Cough responses to inhalation of isotonic solutions containing 150, 75, 37.5 and 0 mM Cl- ions and of capsaicin (0.9-500 mM) were measured. PSS patients with ILD reported a significantly higher cough score than PSS patients without ILD (p<0.03). ILD patients coughed more than those without ILD to Cl- of 37.5 and 0 mM (19.1+/-5.0 vs 6.2+/-1.9 coughs x min(-1) (p<0.03), and 29.2+/-5.0 vs 14.1/-4.1 coughs x min(-1) (p<0.04), respectively). The log concentration of capsaicin causing two or five coughs was lower in PSS with ILD compared to PSS without ILD (0.74+/-0.15 mM vs 2.12+/-0.26 mM; p<0.002). Patients with chronic dry cough had a similar degree of response to low-chloride and capsaicin solutions as patients with PSS and ILD, whilst healthy controls had a similar degrees of response to PSS patients. There is an increased cough reflex in patients with interstitial lung disease, which may represent sensitization of airway sensory nerves. This may be the basis for the chronic dry cough in patients with interstitial lung disease.

Correlation between exhaled nitric oxide, sputum eosinophils, and methacholine responsiveness in patients with mild asthma

BACKGROUND

Eosinophils in induced sputum and exhaled nitric oxide (NO) are currently used as non-invasive markers in the assessment of airway inflammation in asthma. As both sputum eosinophils (%) and exhaled NO are raised in asthmatic subjects not receiving inhaled steroids and decreased following corticosteroid therapy, a relationship between them is plausible.

METHODS

Exhaled NO was measured by chemiluminescence analyser, sputum induction by 3.5% saline inhalation, and bronchial responsiveness was measured as PC20FEV1 methacholine in 35 stable asthmatic patients using beta 2 agonist alone and the correlation between these non-invasive markers of airway inflammation was studied.

RESULTS

There were significant correlations between exhaled NO and PC20 (r = -0.64), exhaled NO and sputum eosinophils (%) (r = 0.48), and also between sputum eosinophils (%) and PC20 (r = -0.40).

CONCLUSION

The correlation between exhaled NO and PC20 suggests that exhaled NO or the mechanisms leading to its increase may contribute to airway hyperresponsiveness in asthma. Furthermore, the relationship between sputum eosinophils (%), exhaled NO, and PC20 highlight the potential use of eosinophils (%) in induced sputum and exhaled NO to monitor the severity of asthma.

Expression and release of interleukin-8 by human airway smooth muscle cells: inhibition by Th-2 cytokines and corticosteroids

Interleukin (IL)-8 is a C-X-C chemokine that potently chemoattracts and activates neutrophils. We determined whether IL-8 could be produced by human airway smooth muscle cells in culture and examined its regulation. TNF-alpha stimulated IL-8 mRNA expression and protein release in a time- and dose-dependent manner, whereas IFN-gamma alone had no effect. Both cytokines together did not induce greater IL-8 release compared to TNF-alpha alone. IL-1beta was more potent in inducing IL-8 release and, together with TNF-alpha, there was a synergistic augmentation of IL-8 release. IL-8 release induced by TNF-alpha and IFN-gamma was partly inhibited by the Th-2-derived cytokines IL-4, IL-10, and IL-13, as well as by dexamethasone. In addition to its contractile responses, airway smooth muscle cells have synthetic and secretory potential with the release of IL-8 and subsequent recruitment and activation of neutrophils in the airways. Release of IL-8 can be modulated by Th-2-derived cytokines and corticosteroids.

Inhaled corticosteroids increase interleukin-10 but reduce macrophage inflammatory protein-1alpha, granulocyte-macrophage colony-stimulating factor, and interferon-gamma release from alveolar macrophages in asthma

We determined the effect of inhaled corticosteroid, budesonide, on the release of the anti-inflammatory cytokine, interleukin-10 (IL-10), and of pro-inflammatory cytokines, macrophage inflammatory protein-1alpha (MIP-1alpha), interferon-gamma (IFN-gamma), and granulocyte-macrophage colony-stimulating factor (GM-CSF), from blood monocytes and alveolar macrophages of mild asthmatic subjects in a double-blind, cross-over, placebo-controlled study. Budesonide reduced bronchial hyperresponsiveness and improved baseline FEV1. Alveolar macrophages were obtained by bronchoalveolar lavage performed at the end of each treatment phase. IL-10 from blood monocytes was not altered, but both IL-10 mRNA and protein expression from alveolar macrophages stimulated by lipopolysaccharide and IL-1beta were increased after corticosteroid therapy. By contrast, alveolar macrophages released significantly less MIP-1alpha, IFN-gamma, and GM-CSF after steroid treatment. In comparison to alveolar macrophages from normal nonasthmatic volunteers, those from asthmatic patients released more MIP-1alpha, IFN-gamma, and GM-CSF but lower amounts of IL-10 particularly at baseline and after IL-1beta stimulation. The ability of steroids to inhibit pro-inflammatory cytokines but to enhance the anti-inflammatory cytokine such as IL-10 may contribute to their beneficial actions in asthma. Asthma is characterized by alveolar macrophages exhibiting both an enhanced capacity to release pro-inflammatory cytokines and a reduced capacity to produce IL-10.

Synthetic and model computational studies of molar rotation additivity for interacting chiral centers: a reinvestigation of van't Hoff's principle

When plane-polarized light impinges on a solution of optically active molecules, the polarization of the light that emerges is rotated. This simple phenomenon arises from the interaction of light with matter and is well understood, in principle, van't Hoff's rule of optical superposition correlates the molar rotation with the individual contributions to optical activity of isolated centers of asymmetry. This straightforward empirical additivity rule is rarely used for structure elucidation nowadays because of its limitations in the assessment of conformationally restricted or interacting chiral centers. However, additivity can be used successfully to assign the configuration of complex natural products such as hennoxazole A if appropriate synthetic partial structures are available. Therefore, van't Hoff's principle is a powerful stereochemical complement to natural products' total synthesis. The quest for reliable quantitative methods to calculate the angle of rotation a priori has been underway for a long time. Both classical and quantum methods for calculating molar rotation have been developed. Of particular practical importance for determining the absolute structure of molecules by calculation is the manner in which interactions between multiple chiral centers in a single molecule are included, leading to additive or non-additive optical rotation angles. This problem is addressed here using semi-empirical electronic structure models and the Rosenfeld equation.

Prediction of myelotoxicity using semi-quantitative marrow image scores

Marrow radiation with resultant myelosuppression is usually dose-limiting in radioimmunotherapy (RIT). This study evaluated the relationship between a semiquantitative score of radiolabeled antibody marrow uptake obtained by imaging and subsequent decrease in peripheral blood cell counts in a patient population in whom marrow malignancy is common.

METHODS

Semiquantitative scores were assigned to lumbar marrow images of 18 patients acquired 0, 6, 24 and 48 hr after the first therapy dose of 131I-Lym-1. Scores were adjusted for injected dose (GBq) and body surface area (m2), and correlated with post-therapy blood counts. A well-defined scale, where 0 and 4 represented least to highest marrow uptake when compared to background, was used to assign marrow image scores. Injected doses of 131I-Lym-1 ranged from 1.1-8.2 GBq (29-222 mCi).

RESULTS

Linear regression of summed marrow scores (0-24 hr after injection) versus decrease in cell counts produced correlation coefficients of 0.76, 0.44, 0.58 and 0.46 for platelets, granulocytes, white blood cells (WBC) and hematocrit, respectively. Scores for individual and other combinations of images obtained immediately up to 24 hr after injection were also predictive.

A forty-year experience with anal carcinoma: changing trends and impact of multimodality therapy

Anal canal carcinoma is a rare clinical entity accounting for 1 to 3 per cent of all gastrointestinal malignancies. Abdominoperineal resection used to be the primary modality of treatment. However, recurrence rates of 20 to 40 per cent were observed after this mutilating procedure. In recent years, multimodality therapy with radiation and chemotherapy has shown at least equal results with the intention to preserve sphincter function. The objective of this study is to describe our experience at Harbor-UCLA Medical Center during the past 4 decades (1955-95), emphasizing changes in demographics, clinical presentation, and impact of multimodality therapy. Seventy-eight patients with the diagnosis of anal canal carcinoma were included. A steady increase in the incidence of anal carcinoma in younger people was observed (24% less than 64 years old for the 1955-65 period versus 75% for 1986-95 period). A female predominance was found in 1955-65 period, with F:M ratio 1.5, and a majority of male cases was seen in the last period (1986-95). Abdominoperineal resection was the preferred treatment during 1955-65, whereas during 1986-95 chemoradiation was the treatment of choice. We observed a trend from primary surgical treatment toward chemoradiotherapy with improvement in survival and preservation of ano-rectal function. Since 1988, we have not performed an abdominoperineal resection for primary treatment of anal carcinoma. Survival analysis was made grouping the patient population according to primary treatment. Higher survival rates were observed in the groups that received chemoradiotherapy (P = 0.0368) either as adjuvant or primary therapy. Chemoradiotherapy should be recommended as primary therapy to most patients.

Simulation and fabrication of attenuated phase-shifting masks: CrF(x)

To acquire the required resolution for 248- and 193-nm lithography, a study of attenuated phase-shifting mask (Att-PSM) technology is in progress. We performed a simulation study using a matrix method to calculate relative transmittance and the amount of phase shift of light through the PSM. However, we found that the average film composition changed with deposition time. Accordingly, optical constants were found to be a strong function of film thickness. Therefore we rearranged the relationship between deposition parameters (e.g., deposition time or gas flow rate ratio) and optical constants (e.g., refractive index and extinction coefficient) to extract the empirical formula for the optical constants with respect to film composition. To verify our simulation study, we fabricated a phase shifter based on our simulation result, which was found to have a transmittance of 8.3% and a phase shift of 179.5 degrees . Consequently, we obtained a reliable optimum condition for the deep-ultraviolet Att-PSM.

Impaired resistance to the development of toxoplasmic encephalitis in interleukin-6-deficient mice

The role of interleukin-6 (IL-6) in the pathogenesis of toxoplasmic encephalitis (TE) was examined by using IL-6-targeted mutant (IL-6(-/-)) mice. At 4 and 8 weeks after infection with the ME49 strain of Toxoplasma gondii, significantly greater numbers of T. gondii cysts and areas of inflammation associated with tachyzoites were observed in brains of IL-6(-/-) mice than in those of control mice. Large areas of necrosis were observed only in brains of IL-6(-/-) mice. Tachyzoites were frequently detected in the areas of necrosis, suggesting that necrosis was caused by proliferation of the parasite. These results indicate that IL-6 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in brains of infected mice. Whereas in brains of control mice, large numbers of inflammatory cells were always observed in areas where tachyzoites were detected, in brains of IL-6(-/-) mice, only small numbers of inflammatory cells were observed in many areas with tachyzoites. Lymphocyte preparations isolated from brains of infected control mice had significantly higher ratios of gamma/delta T cells and CD4+ alpha/beta T cells but lower ratios of CD8+ alpha/beta T cells compared to those of infected IL-6(-/-) mice. There were no differences in the ratios of these T-cell subsets in spleens between these mice. The amounts of mRNA for gamma interferon (IFN-gamma) detected by reverse transcriptase PCR were significantly smaller in brains of IL-6(-/-) mice than in those of control mice, whereas amounts of IL-10 mRNA were greater in the former than in the latter. IL-6 mRNA was detected only in infected control mice. The protective activity of IL-6 against development of TE appears to be through its ability to stimulate IFN-gamma production and induce infiltration and accumulation of different T-cell subsets in brains of infected mice.

Mitochondrial gene transfer ribonucleic acid (tRNA)Leu(UUR) 3243 and tRNA(Lys) 8344 mutations and diabetes mellitus in Korea

The high prevalence of diabetic patients with a mutation in the mitochondrial gene (the 3243 and 8344 bp mutations) has been identified in Japan. To determine the prevalence of diabetic patients with those mutations in Korea, we randomly screened selected 503 clinical diabetic patients regardless of their diabetes types. We found only 1 patient with the mitochondrial DNA mutation at position 3243 (percent mutation, 32%), and the mitochondrial DNA mutation at position 8344 was not found in any of the patients. The affected subject was a 22-yr-old man with a history of myoclonic epilepsy and mild sensorineural hearing loss, a 1-yr duration of diabetes mellitus, and a low level C peptide response to oral glucose. Because of the low frequency of these mutations in the Korean diabetic population, we concluded that these particular mutations of mitochondrial DNA may not be a common contributor to diabetes mellitus in Korea.

IL-4 is protective against development of toxoplasmic encephalitis

IFN-gamma is critical for prevention of development of toxoplasmic encephalitis (TE). Since IL-4 down-regulates production of IFN-gamma, we examined its role in the pathogenesis of TE in IL-4-targeted mutant (IL-4-/-) mice. IL-4-/- mice all died from 6 to 20 wk after peroral infection with cysts of the ME49 strain of Toxoplasma gondii; control mice survived. At 4 and 8 wk after infection, significantly greater numbers of T. gondii cysts and foci of acute inflammation, and greater amounts of tachyzoite-specific mRNA (by reverse-transcriptase PCR) were in brains of IL-4-/- mice than controls. Toxoplasma IgG2b and IgG3 Ab levels were slightly but significantly higher in sera of IL-4-/- than control mice, whereas IgM and IgG2a levels did not differ between these mice. Toxoplasma IgG1 and IgE Abs were not detected in sera of either strain. Amounts of IFN-gamma, TNF-alpha, IL-6, and IL-10 mRNA detected by reverse-transcriptase PCR did not differ between brains of infected IL-4-/- and controls, although brains of the former mice had greater numbers of inflammatory mononuclear cell infiltrates. IL-4 mRNA was detected only in infected control mice. Spleen cells of control mice at 8 wk after infection produced significantly greater amounts of IFN-gamma following stimulation in vitro with soluble T. gondii Ags than did those from IL-4-/- mice. These results indicate that IL-4 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in the brain. The impaired ability of IL-4-/- mice in the late stage of T. gondii infection to produce IFN-gamma most likely contributes to their susceptibility for development of severe TE.

IL-4 is protective against development of toxoplasmic encephalitis

IFN-gamma is critical for prevention of development of toxoplasmic encephalitis (TE). Since IL-4 down-regulates production of IFN-gamma, we examined its role in the pathogenesis of TE in IL-4-targeted mutant (IL-4-/-) mice. IL-4-/- mice all died from 6 to 20 wk after peroral infection with cysts of the ME49 strain of Toxoplasma gondii; control mice survived. At 4 and 8 wk after infection, significantly greater numbers of T. gondii cysts and foci of acute inflammation, and greater amounts of tachyzoite-specific mRNA (by reverse-transcriptase PCR) were in brains of IL-4-/- mice than controls. Toxoplasma IgG2b and IgG3 Ab levels were slightly but significantly higher in sera of IL-4-/- than control mice, whereas IgM and IgG2a levels did not differ between these mice. Toxoplasma IgG1 and IgE Abs were not detected in sera of either strain. Amounts of IFN-gamma, TNF-alpha, IL-6, and IL-10 mRNA detected by reverse-transcriptase PCR did not differ between brains of infected IL-4-/- and controls, although brains of the former mice had greater numbers of inflammatory mononuclear cell infiltrates. IL-4 mRNA was detected only in infected control mice. Spleen cells of control mice at 8 wk after infection produced significantly greater amounts of IFN-gamma following stimulation in vitro with soluble T. gondii Ags than did those from IL-4-/- mice. These results indicate that IL-4 is protective against development of TE by preventing formation of T. gondii cysts and proliferation of tachyzoites in the brain. The impaired ability of IL-4-/- mice in the late stage of T. gondii infection to produce IFN-gamma most likely contributes to their susceptibility for development of severe TE.

Ictal scalp EEG in temporal lobe epilepsy with unitemporal versus bitemporal interictal epileptiform discharges

We investigated the ictal scalp EEG in 228 seizures of 36 patients with unitemporal (n = 25) or bitemporal independent (n = 11) interictal epileptiform discharges (IED). All patients had proven temporal lobe epilepsy since they became seizure-free or only had auras after temporal lobectomy with a minimum follow-up of 1 year. Ictal patterns at seizure onset or later in the course of the seizure were lateralized significantly more often in patients with unitemporal IED (90%, at seizure onset and 96%, later) compared with those with bitemporal independent IED (75%, at seizure onset and 78%, later). Furthermore, scalp ictal EEGs, when lateralized at seizure onset or later in the course of the seizure, were significantly more likely to predict the correct side for surgery in patients with unitemporal (98%, at seizure onset and 100%, later) than bitemporal (64%, at seizure onset and 77%, later) IED. Bilateral independent seizure onsets, asynchrony of ictal activity over the two temporal lobes, and switch of ictal activity from one to the other hemisphere are ictal patterns that are strongly correlated with bitemporal excitability.

Randomized trial of intravenous immunoglobulin prophylaxis for patients with chronic lymphocytic leukaemia and secondary hypogammaglobulinaemia

Forty-two patients with chronic lymphocytic leukaemia (CLL), serum IgG levels < 5.5 milligrams and a history of two or more recent infections, were randomized to receive infusions of 18 g human intravenous immunoglobulin (IVIg) or human albumin placebo every three weeks. During the 12 month study 122 infections were documented but only four were associated with neutropenia. Ten patients (24%) with IgG levels < 3.0 milligrams experienced 65% of the infections. In response to IVIg there were immediate and accumulative increases in serum IgG levels and an associated decrease in total and serious infections. If three further infections occurred, placebo patients were commenced on 18 g IVIg, and IVIg patients were increased to 24 g IVIg. Approximately 50% of these cases subsequently remained infection free. The study shows the usefulness of prophylactic Sandoglobulin in CLL patients with hypogammaglobulinaemia, and suggests that this may be justified in those with recurrent infections and serum IgG levels < 3 milligrams.

Variability and reproducibility of rubidium-82 kinetic parameters in the myocardium of the anesthetized canine

Kinetic analysis of 82Rb dynamic PET data produces quantitative measures which could be used to evaluate ischemic heart disease. These measures have the potential to generate objective comparisons of different patients or the same patient at different times. To achieve this potential, it is essential to determine the variability and reproducibility of the kinetic parameters.

METHODS

A total of 48 82Rb dynamic PET datasets were acquired from two pure bred beagles. Each animal underwent eight 82Rb PET studies with essentially the same protocol for three successive weeks. Data were acquired with the Donner 600-Crystal Positron Tomograph (PET600). In each week, single-slice dynamic 82Rb PET datasets were collected with the animal at rest at three different gantry positions separated by 5 mm. Additional dataset were collected after dipyridamole infusion and after administration of aminophylline to induce a return to rest. A two-compartment kinetic model with correction for myocardial vasculature and spillover from the left ventricular blood pool was used to analyze the dynamic datasets. Model parameters for uptake (k1), washout (k2) and vascular fraction (fv) were estimated in 11-14 myocardial regions of interest (ROIs) using a weighted least-squares criterion. Statistical fluctuation due to the PET acquisition process was minimized by using a relatively high 82Rb dose (about 30 mCi) to take advantage of the high count rate capacity of the PET600.

RESULTS

The variation in mean k1, where the mean is taken over the myocardial ROIs was 10%-20% (Dog 1) and 15%-50% (Dog 2) among the rest studies conducted on the same date. Similar variation was evident in comparing studies in the same animal for different weeks.

CONCLUSION

Spatial and temporal variation in estimates of the uptake rate (k1) of 82Rb in the resting myocardium of the anesthetized canine are small in relation to the functional increase in k1 following dipyridamole infusion.

Regulation of retinal ganglion cell axon arbor size by target availability: mechanisms of compression and expansion of the retinotectal projection

The ability of pre- and postsynaptic populations to achieve the proper convergence ratios during development is especially critical in topographically mapped systems such as the retinotectal system. The ratio of retinal ganglion cells to their target cells in the optic tectum can be altered experimentally either by early partial tectal ablation, which results in an orderly compression of near-normal numbers of retinal projections into a smaller tectal area, or by early monocular enucleation, which results in the expansion of a reduced number of axons in a near-normal tectal volume. Our previous studies showed that changes in cell death and synaptic density consequent to these manipulations can account for only a minor component of this compensation for the population mismatch. In this study, we examine other mechanisms of population matching in the hamster retinotectal system. We used an in vitro horseradish peroxidase labeling method to trace individual retinal ganglion cell axons in superior colliculi partially ablated on the day of birth, as well as in colliculi contralateral to a monocular enucleation. We found that individual axon arbors within the partially lesioned tectum occupy a smaller area, with fewer branches and fewer terminal boutons, but preserve a normal bouton density. In contrast, ipsilaterally projecting axon arbors in monocularly enucleated animals occupy a greater area than in the normal condition, with a much larger arbor length and greater number of boutons and branches compared with normal ipsilaterally projecting cells. Alteration of axonal arborization of retinal ganglion cells is the main factor responsible for matching the retinal and tectal cell populations within the tectum. This process conserves normal electrophysiological function over a wide range of convergence ratios and may occur through strict selectivity of tectal cells for their normal number of inputs.

African-American marriage in 1910: beneath the surface of census data

This paper examines the quality of information about marital status, marital duration, and marriage order among African-American women in the U.S. Census of 1910. It compares the reported prevalence of widowhood to estimates of widowhood based on the mortality of black men and on the ages of women at first marriage. It also compares the reported distributions of duration of first marriage to estimates based on mortality and on age at first marriage. It concludes that census reports are subject to serious error. Widowhood is overreported, and marital turnover appears to have been faster than implied by census reports. The prevalance of "own children" is used to confirm these conclusions and to suggest motivations for misreporting.

Selective targeting of p53 gene mutational hotspots in human cancers by etiologically defined carcinogens

In lung and liver cancers, p53 mutations are mostly G:C to T:A transversions. This type of mutation is known to be induced by benzo(a)pyrene and aflatoxin B1 which are associated with the etiology of lung and liver cancers, respectively. Using a novel assay based on DNA polymerase fingerprint analysis, we identified p53 nucleotides targeted by these carcinogens. Thirteen of 14 nucleotide residues of the p53 gene which underwent G:C to T:A mutations in lung cancers were targeted by benzo(a)pyrene. Similarly, aflatoxin B1 formed adducts at a mutational hotspot specific for liver cancer. The same nucleotide (third base of codon 249), which mutates rarely in lung cancers, was not a target for benzo(a)pyrene. These in vitro observations indicate that p53 mutational hotspots identified in different tumors are selected targets specifically for the etiologically defined environmental carcinogens.

Tolerance during 5 months of dosing with ranitidine, 150 mg nightly: a placebo-controlled, double-blind study

Repeated dosing with an H2-receptor antagonist results in a modest decrease in antisecretory potency termed "tolerance." The object of this prospective study was to determine whether tolerance is a progressive phenomenon or whether it levels off during prolonged dosing with a standard maintenance dose of an H2-antagonist. The effect of continuous dosing with ranitidine, 150 mg nightly, was compared with intermittent dosing (27 days of placebo each month) with active ranitidine, 150 mg nightly, only on the night of each experiment. Simultaneous 24-hour intragastric acidity and plasma gastrin concentration were measured monthly for 5 months in 17 healthy subjects (7 continuous and 10 intermittent dosing). In the intermittent-dosing group, the antisecretory response to ranitidine, 150 mg nightly, was preserved throughout the 141-day trial period; the median nocturnal integrated acidity decreased from 557 mmol.h/L (day 0) to 38 mmol.h/L on day 1 of dosing, and it ranged between 32 and 55 (median, 45) mmol.h/L during days 29-141. In the continuous-dosing group, there was a significant return of nocturnal intragastric acidity on days 29 and 85 compared with day 1 of dosing. The median nocturnal integrated acidity decreased in the continuous-dosing group from 554 mmol.h/L (day 0) to 87 mmol.h/L on the first day of dosing, and it ranged between 145 and 287 (median, 170) mmol.h/L during days 29-141. Either intermittent or continuous dosing with ranitidine was associated with an elevation of plasma gastrin concentration, which remained constant throughout the 5-month study. Tolerance does develop in healthy subjects during the first month of dosing with ranitidine, 150 mg nightly, but it is not a progressive phenomenon, and it is probably not of clinical relevance.

Induction of long-term survival of hamster heart xenografts in rats

The aim of this study was to determine the mechanisms responsible for concordant xenograft rejection using the hamster-to-rat heart graft model. Even though it was known that rat CD4 positive T cells proliferated to hamster stimulators in mixed lymphocyte reactions, the depletion of CD4 positive T cells in rat recipients did not lead to an extension of xenograft survival. Suppression of T cell immunity using other monoclonal antibodies or cyclosporine also failed to improve survival. Only by depleting complement with cobra-venom factor could hamster xenograft survival be prolonged, and long-term survival was achieved by combining CsA with COF. High-antibody titers to hamster cells were found after transplantation of hamster hearts, and evidence is presented that rejection of these "concordant" xenografts is mediated primarily by antibody-complement mechanisms. The antihamster antibodies were produced in the absence of T cell help, which suggests that antibody-mediated graft destruction cannot be inhibited by suppression or depletion of T cells. Pharmacologic depletion of complement for the clinical application of concordant xenografts is a promising avenue of future research.

The effects of epoxidized xenobiotics on mitogen responsiveness and antibody-producing ability of murine spleen cells in vitro

The effects of benzo(a)pyrene [B(a)P], B(a)P-4,5- and 7,8-dihydroepoxide, (+)-B(a)P-7,8-diol, (-)-B(a)P-7,8-diol, cholestan-5 alpha,6 alpha-epoxy-3 beta-ol, cholestan-5 beta,6 beta-epoxy-3 beta-ol, cholestantriol and styrene oxide, on the in vitro mitogen responses and antibody-producing ability of mouse spleen cells were evaluated. B(a)P suppressed the plaque-forming cell (PFC) response to T-cell dependent antigen sheep red blood cells (SRBC), but had no effect on the proliferative response to mitogens (phytohemagglutinin, concanavalin A and lipopolysaccharides) except a slight but significant increase to concanavalin A at lower doses. B(a)P-4,5- and 7,8-dihydroepoxides completely inhibited the proliferative response at concentrations exceeding 10(-6) M, but lower concentrations were without any effect. These two epoxides also suppressed the PFC response at concentration greater than or equal to 10(-5) M. This was accompanied by reduced cell viability. (+)-B(a)P-7,8-diol produced a dose-dependent suppression of PFC response to SRBC without altering the cell viability. The proliferative response was inhibited only at concentration greater than or equal to 10(-4) M. In contrast, (-)-B(a)P-7,8-diol has no effect on the PFC response and suppressed the proliferative response only at concentration of greater than or equal to 10(-5) M. Cholestan compounds had no effect on the plaque-forming cell response at concentrations less than or equal to 10(-5) M. The effects on the proliferative response to mitogens were inhibitory and stimulatory depending upon the dose used. Styrene oxide neither inhibited the PFC nor the proliferative responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocytosed beta-VLDL and LDL are delivered to different intracellular vesicles in mouse peritoneal macrophages

Hypercholesterolemic rabbit beta-VLDL and human LDL are both internalized by mouse peritoneal macrophages by receptor-mediated endocytosis. However, only beta-VLDL (which binds to the cells with a much higher affinity than LDL) markedly stimulates acyl-CoA/cholesterol acyl transferase (ACAT) and induces foam cell formation in these cells. As an initial step to test whether the two lipoproteins might be targeted to different organelles (which might differ in their ability to deliver cholesterol to microsomal ACAT), we studied the endocytic pathways of beta-VLDL and LDL. Lipoproteins were labeled with the non-transferable fluorescent label, DiI. When the macrophages were incubated with DiI-LDL for 10 min at 37 degrees C, the fluorescence was concentrated near the center of the cell both in heavily labeled vesicles and in a diffuse pattern. The pattern with DiI-beta-VLDL was quite different: an array of bright vesicles throughout the cytoplasm was the predominant feature. Differences in distribution were seen as early as 2 min of incubation and persisted throughout a 10-min chase period. By using a procedure in which photobleaching of DiI fluorescence converts diaminobenzidine into an electron-dense marker, we were able to identify at the ultrastructural level vesicles containing electron-dense material in cells incubated with DiI-beta-VLDL. Human E2/E2 beta-VLDL (from a patient with familial dysbetalipoproteinemia), which has a binding affinity and ACAT-stimulatory potential similar to LDL, gave a pattern of fluorescence virtually identical to LDL. Pulse-chase studies with 125I-labeled and [3H]cholesteryl ester-labeled lipoproteins disclosed that both protein degradation and cholesteryl ester hydrolysis were markedly retarded in beta-VLDL compared with LDL. Thus, in mouse peritoneal macrophages, endocytosed beta-VLDL appears in a distinct set of widely-distributed vesicles not seen with LDL (or with E2-beta-VLDL) and, compared with LDL, has a markedly diminished rate of protein degradation and cholesteryl ester hydrolysis. The differential routing of LDL and beta-VLDL may provide a mechanism for differences in ACAT-stimulatory potential between the two lipoproteins.

Novel metabolism of several beta zero-thalassemic beta-globin mRNAs in the erythroid tissues of transgenic mice

Mice that are transgenic for human beta zero-thalassemic beta-globin alleles were generated in order to study how beta zero-thalassemic mutations affect beta-globin RNA metabolism in erythroid tissues. Three thalassemic alleles were studied, each of which harbors either a frameshift or a nonsense mutation. These mutations result in the premature termination of beta-globin mRNA translation and an abnormally low level of beta-globin mRNA in the peripheral blood of thalassemic patients. Comparative studies of mice that express any of the beta zero-thalassemic transgenes with mice that express a normal human beta-globin transgene demonstrated that all three thalassemic mRNAs are metabolized in erythroid tissues abnormally. RNA blotting and S1 nuclease transcript mapping revealed for each thalassemic transgene that (i) the full-length mRNA is abnormally short-lived and (ii) in addition to full-length mRNA, three more stable yet smaller RNAs are present. These smaller RNAs are polyadenylated and lack the mRNA 5' end.

Ventral mesencephalic neurons containing both cholecystokinin- and tyrosine hydroxylase-like immunoreactivities project to forebrain regions

The coexistence of cholecystokinin- and tyrosine hydroxylase-like immunoreactivities within neurons of the rat ventral mesencephalon was analyzed by using an indirect immunofluorescence technique for the simultaneous demonstration of two antigens in the same tissue section. A high degree of colocalization was observed in the substantia nigra pars compacta, in which 80-90% of all labeled neurons at rostral and up to 70% at intermediate levels contained both cholecystokinin and tyrosine hydroxylase. At caudal levels, the incidence of colocalization declined to approximately 30-50%. All of the immunoreactive perikarya in the substantia nigra pars lateralis were labeled with both substances. Other areas of the ventral midbrain that exhibited a moderate proportion of neurons immunoreactive for both cholecystokinin and tyrosine hydroxylase included the ventral tegmental area, interfascicular nucleus, and rostral and caudal linear nuclei. In addition, coexistence was occasionally observed within neurons of the central and ventral periaqueductal gray matter, supramammillary region, peripeduncular region, retrorubral field, and extremely rarely, within the substantia nigra pars reticulata. Cell bodies containing tyrosine hydroxylase-like immunoreactivity (indicative of dopamine) usually outnumbered those containing the peptide except in the supramammillary region and in the ventral periaqueductal gray matter, where the cholecystokinin perikarya were present in higher numbers. The double-labeling colocalization technique was combined with fluorescence retrograde tracing to determine some of the forebrain projections of these neurons. Ventral midbrain neurons containing both cholecystokinin and tyrosine hydroxylase were found to project to the caudate-putamen, nucleus-accumbens, prefrontal cortex, and amygdala. These projections originated from neurons located predominantly in the substantia nigra pars compacta and the ventral tegmental area. Thus, cholecystokinin occurs within the well-known dopaminergic nigrostriatal pathway in the rat. Overall, these results demonstrate that a significant proportion of the dopamine neurons giving rise to the ascending mesotelencephalic projections also contain the peptide cholecystokinin.

Thrombocytopenia following routine blood transfusion: micro-aggregate blood filters prevent worsening thrombocytopenia in patients with low platelet counts

11 patients with anaemia and thrombocytopenia due to bone marrow failure each received 2 sets of red-cell transfusions. They were randomised to receive 1 blood transfusion through a standard 170-micron giving set filter and another through a 40 micron micro-aggregate filter. After transfusion, the mean fall in platelet count was 15 x 10(9)/l (41.7%) and 1.4 x 10(9)/l (4.6%), respectively (p less than 0.01). The results confirm the findings of a previous study which showed that micro-aggregate filters prevent a post-transfusional decrease in platelet counts. In addition, this new study shows that this is clinically relevant in patients who are thrombocytopenic at the time of their blood transfusion.

Reaction of pyruvate kinase with the new nucleotide affinity labels 8-[(4-bromo-2,3-dioxobutyl)thio]adenosine 5'-diphosphate and 5'-triphosphate

Two new reactive nucleotides have been synthesized and characterized: 8-[(4-bromo-2,3-dioxobutyl)thio]adenosine 5'-diphosphate and 5'-triphosphate (8-BDB-TADP and 8-BDB-TATP). ADP or ATP was converted to 8-thio-ADP (-ATP) via 8-bromo-ADP (-ATP), followed by condensation with 1,4-dibromobutanedione. Rabbit muscle pyruvate kinase is inactivated by both reagents in a biphasic manner with an initial rapid loss of 75% activity, followed by a slow total inactivation. The initial fast reaction with both compounds exhibits nonlinear dependence on reagent concentration, indicating formation of a reversible enzyme-reagent complex prior to covalent attachment. The presence of the gamma-phosphoryl group improves the performance of the affinity label: KI values for the fast phase are similar (about 100 microM), whereas kmax for 8-BDB-TATP is about three times greater than that of 8-BDB-TADP (0.286 min-1 vs 0.0835 min-1). After an 80-min incubation with 175 microM of either reagent, about 2 mol/mol of subunit is incorporated with 76% inactivation caused by 8-BDB-TADP and 97% inactivation by 8-BDB-TATP. Loss of activity is prevented by substrates, with the best protection afforded by a combination of ATP, Mn2+, K+, and phosphoenolpyruvate. Reaction of pyruvate kinase with either compound in the presence of protecting ligands leads to incorporation of about 1 mol of reagent/mol of subunit with only about 15% loss of activity. These results suggest that 8-BDB-TADP and 8-BDB-TATP react with two groups on the enzyme, one of which is at or near the active site.(ABSTRACT TRUNCATED AT 250 WORDS)