Inhibitory cytokines in asthma

Although research in asthma has concentrated on complex proinflammatory mechanisms, it is likely that defective expression of cytokines that inhibit allergic inflammation, such as interleukin 10, interleukin 12 and interferon gamma, might also be important, particularly in determining disease severity and persistence of inflammation in the airways. Therapy based on these cytokines might also be useful, with the advantage that it restores the balance of endogenous cytokines. We discuss the therapeutic potential of these and other inhibitory cytokines in the treatment of asthma, particularly in patients with severe disease that is poorly responsive to conventional therapy, or as a disease-modifying treatment when used early.

Extramedullary T lymphoblastic transformation of chronic myeloid leukaemia occurring after double allogeneic transplantation

The clinical course of chronic myeloid leukaemia (CML) is characterised by a chronic phase followed by an acute phase or blast crisis. Lymphoid transformation accounts for 20-30% of such events, with the majority of cases being of B cell origin. Extramedullary transformation occurs in approximately 10% of cases. We report a case of T cell lymphoblastic transformation in CML presenting as an extramedullary mass after allogeneic stem cell transplant. This case supports the growing evidence that CML arises in the pluripotent stem cell.

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.