The protective effect of preconditioning on reperfusion-induced arrhythmia is lost by treatment with superoxide dismutase

The purpose of this study was to investigate the relation between free radicals and the effect of preconditioning on reperfusion arrhythmias using the isolated working rat heart model. Rats were divided into 3 groups: control, preconditioned without superoxide dismutase (SOD) and preconditioned with SOD (n = 8 each group). The incidence of reperfusion-induced ventricular fibrillation (Vf) in the preconditioned without SOD group was reduced from 100% to 13% (p < 0.005 vs control). This protective effect of preconditioning was not observed in the SOD-treated group (incidence of Vf increased from 13% to 75%, p < 0.025). The protective effect of preconditioning on reperfusion arrhythmias is related to the presence of oxygen free radicals which occur during the reperfusion period of the preconditioning phase.

Antiphospholipid antibodies. A prognostic factor in sarcoidosis?

Serum antibodies against five types of phospholipids, antiphospholipid antibodies (aPL), were determined by an enzyme-linked immunosorbent assay in 55 patients with sarcoidosis. Either IgG or IgM aPL were detected in 21 patients (38 percent). This positive rate was significantly higher than that (7 percent) of healthy control subjects (p < 0.001). In terms of immunoglobulin classes, 5 cases had IgG aPL only, 11 cases had IgM aPL only, and 5 cases had both classes of aPL. No correlation was observed between the occurrence of aPL and disease activity of sarcoidosis. A significant correlation was noted between the occurrence of aPL and many extrathoracic organ lesions or the persistence of abnormal chest x-ray film findings for periods of 2 and 5 years. Taken together, the presence of aPL in sarcoidosis is a useful index to judge the prolongation of the disease.

Molecular characterization of a novel serine protease involved in activation of the complement system by mannose-binding protein

Mannose-binding protein (MBP) plays an important role in host defense by recognizing sugar residues on certain pathogens and activating the complement cascade. Recently, we described a new protease, designated MBP-associated serine protease (MASP) which is required for complement activation by MBP. We have cloned the cDNA that encodes this protease and found that the deduced amino acid sequence contains an epidermal growth factor-like domain, two short consensus repeats and a serine protease domain. The overall structure of MASP is similar to serine proteases of the first complement component complex, C1r-C1s. Unlike C1r-C1s, however, MASP has a histidine loop structure common to many serine proteases such as trypsin and chymotrypsin. The MASP gene was mapped on the long arm of chromosome 3 which is different from C1r-C1s as well as from trypsin and chymotrypsin. These findings suggest that MASP may have emerged prior to C1r-C1s from a common ancestor. This implies that MBP-MASP, a complex of lectin and serine protease, presumably evolved prior to adaptive immune recognition involving antibody and the classical complement pathway.

Resolution of 4-(4-chlorobenzyl)-2-(hexahydro-1-methyl-1H-azepin-4yl)-1(2H)-phthalazi none enantiomers in plasma with frit-FAB LC-MS using a conalbumin column

A new column-switching method for analysis of drug enantiomers in plasma has been developed with liquid chromatography-frit fast atom bombardment mass spectrometry in combination with a chiral resolution column, which consists of conalbumin (egg-white glycoprotein) immobilized on silica gel and can be used in the reversed-phase separation mode. This method makes it possible to inject a large volume of deproteinized plasma and obtain resolution of drug enantiomers with high sensitivity. The optimum mobile phase, including a non-volatile buffer such as phosphate buffer, for separation of drugs from a large amount of endogenous compounds can be used, because of inclusion of a trapping column with a desalting function. This method is very simple and rapid, and should be very powerful in studies requiring high-sensitivity analysis with chiral separation of drugs from biological samples such as plasma.

[Effect of nifedipine and enalapril on cardiac autonomic activity in elderly hypertensive patients]

To clarify the effect of the calcium antagonist Nifedipine and the ACE inhibitor Enalapril on cardiac autonomic activity, power spectral analysis of heart rate variability (PSA) was conducted in 39 elderly patients with essential hypertension (mean age: 63: +/- 11 years) before and after treatment. Twenty patients were treated with 10-20 mg of Nifedipine (N group) and 19 with 5 mg of Enalapril (E group) for 3 months. beta-blocker (Atenolol 12.5 mg) was added to Nifedipine in 12 patients of the N group for 1 month, and the modified effect of Atenolol on cardiac autonomic activity was also evaluated. Blood pressures were significantly reduced in both N and E groups after the treatment. The low frequency component (LF) in PSA, which was considered to be a quantitative marker of cardiac sympathetic activity, increased significantly and the high frequency component (HF), which was a marker of cardiac parasympathetic activity, significantly decreased with increase of PNA levels in N group after the treatment. However, the LF decreased significantly after addition of Atenolol. On the other hand, there was little significant change in LF and PNA in E group. These results suggest that Nifedipine increased cardiac sympathetic activity and that Enalapril had little influence on the cardiac sympathetic tone, while both antihypertensive agents significantly reduced blood pressure itself.

[A case of aspirin-induced asthma which developed due to rubbing a lotion containing a non-steroidal anti-inflammatory drug, ketoprofen, on the skin]

A forty-year-old woman was admitted to our hospital because of a severe attack of bronchial asthma. The asthmatic attack developed 3 hours after her rubbing a large amount of a lotion containing a non-steroidal anti-inflammatory drug (NSAID), ketoprofen, over her skin. The patient had a past history of asthmatic attack induced by another NSAID (Sedes-G) given per os. The previous asthmatic attack developed about 3 hours after her rubbing the lotion containing the NSAID over her skin. The relatively long interval between the per cutaneous NSAID administration and the onset of the asthmatic attack indicates that the time delay is dependent on the absorption route of the administered NSAID. The severity of the attack is considered to be related to the amount of NSAID absorbed.

Arachidonic acid liberation induced by phosphatidic acid endogenously generated from membrane phospholipids in rabbit platelets

The action of phosphatidic acid generated from membrane phospholipids on phospholipase A2 activation in rabbit platelets was investigated. When [3H]arachidonic acid-labelled platelets were treated with phorbol 12-myristate 13-acetate (PMA) and the membranes isolated from the cells incubated at 37 degrees C with 50 microM CaCl2 and 50 microM guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), both phosphatidic acid production and arachidonic acid liberation increased in PMA- and GTP gamma S-concentration-dependent manners. Ethanol dose-dependently inhibited these responses, accompanied by the formation of phosphatidylethanol. Since propranolol, an inhibitor of phosphatidic acid phosphohydrolase, had no influence on the production of phosphatidic acid, the arachidonic acid liberated does not appear to be derived from diacylglycerol which may be produced from phosphatidic acid through the action of this enzyme. In another approach, treatment of [3H]arachidonic acid-labelled membranes with phospholipase D from Streptomyces chromofuscus induced arachidonic acid liberation as well as phosphatidic acid formation in time- and dose-dependent manners. The former response was suppressed by p-bromophenacyl bromide, a phospholipase A2 inhibitor. These results suggest that phosphatidic acid derived from membrane phospholipids potentiates phospholipase A2 activation and contributes to the amplification of platelet activation.

Cloning and sequencing of a cDNA encoding the rat Bcl-2 protein

A rat cDNA encoding the Bcl-2 protein was cloned and sequenced. The primary amino-acid sequence deduced from the nucleotide sequence reveals a 236-aa protein having extensive homology with the mouse (95%), human (87%) and chicken (71%) Bcl-2 proteins.

Structure of [2Fe—2S] ferredoxin I from Equisetum arvense at 1.8 Å resolution

Ferredoxin I (Fd I) from Equisetum arvense is an iron-sulfur protein composed of 95 amino-acid residues and one [2Fe-2S] cluster. It crystallized in the space group P2(1), a = 30.4, b = 57.4, c = 47.5 A and beta = 78.7 degrees with two molecules per asymmetric unit. X-ray diffraction data up to 1.8 A resolution were collected by using a Rigaku four-circle diffractometer. The initial model of Fd I, which was derived by the molecular replacement method using a structure of the Fd I from the blue-green alga Aphanothece sacrum, was refined by molecular dynamics simulation and a least-squares minimization with stereochemical restraints. Positional parameters and isotropic temperature factors for 1420 non-H protein atoms and 183 water molecules were refined on 13 838 observed structure factors (F(o) > sigma(Fo)) between 10.0 and 1.8 A resolution. The final Rfactor was 17.0%, and the standard deviation of atomic position estimated by Luzzati plot [Luzzati (1952). Acta Cryst. 5, 802-810] was 0.2 A. The electron-density map was well defined for the two independent molecules except for the N-terminal residue and the three C-terminal residues. Equivalent Calpha atoms of two independent molecules in the asymmetric unit were superposed by the least-squares method with root-mean-square deviations of 0.26 A. Reasonable structural differences were observed at a polypeptide segment having few intramolecular interactions. Highly flexible regions of the molecule were assigned from the structural differences between the two independent molecules in the crystal and the distribution of temperature factors along the polypeptide chain.

Induction of estrogen receptor and cell division in genital tracts of male mice by neonatal exposure to diethylstilbestrol

Estrogen receptor (ER) and ER mRNA expression and cell division induced by neonatal diethylstilbestrol (DES) exposure in male C57BL/Tw mouse genital organs were studied using immunohistochemistry, in situ hybridization, and cell counting at metaphase. A single injection of 3 micrograms DES on the day of birth induced ER in both epithelial (E) and stromal (S) cells of the epididymis and the seminal vesicles, in E cells of the ductus deferens, and in S cells of the ductus efferens and the anterior prostate 24 h after the injection. After 5 daily injections of DES, ER was induced in S cells of the ventral prostrate at 5 days of age. The staining intensity of ER increased in E cells of the epididymis and the ductus efferens at 5 days. A single injection of DES induced ER mRNA in both E and S cells of the ductus efferens, the caput epididymis, and the ductus deferens 4 to 12 h after injection of the newborn mice. A single injection of DES stimulated cell division of both E and S cells in the ductus deferens and the epididymis; cell division of S cells of the ductus efferens, the anterior prostate, and the urethra was stimulated 24 h after the injection. After 5 daily injections of DES, cell division was stimulated significantly in E and S cells of the epididymis, the ductus deferens, and the ventral prostate, and in S cells of the seminal vesicle at 5 days. At 30 days of age, mitotic rates were significantly higher in E cells of the seminal vesicles and the epididymides of mice given 5 daily injections of DES.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation of histochemical properties of masticatory muscles in Bovidae and Cervidae (Artiodactyla)

We analyzed the masticatory muscles (masseter, temporal, medial pterygoid and lateral pterygoid muscles) of Bovidae and Cervidae (Artiodactyla) for the histochemical characteristics of their fiber types. Analysis of muscle fiber types in the present study was based on the staining reaction for SDH, Sudan black B, alpha-GPDH, and myosin-ATPase after alkaline preincubations. Histochemical properties were found to contribute to masticatory function, including a slow-twitch fatigue resistant activity derived from the high percentage of red fibers, in spite of the differences in the distributions of fiber types in three portions (superficial, medial and profound portions) of each masticatory muscle. These results indicate a correlation between the histochemical profiles of individual masticatory muscles in these species and their functions during jaw movements.

Immunodeficiency and IL-6 production by peripheral blood monocytes in multicentric Castleman's disease

To study the pathogenesis of multicentric Castleman's disease (MCD), IL-6 producing cells and immune function were investigated in four MCD patients. The expression of IL-6 mRNA in one MCD lymph node was analysed by in situ hybridization. IL-6 mRNA expressing cells were scattered in the interfollicular areas and did not resemble plasma cells. Spontaneous IL-6 production was detected in the culture supernatants of peripheral blood mononuclear cells (PBMNC) from four patients. The IL-6 producing cells among the PBMNC were found to be monocytes by both in situ hybridization and immunohistochemistry. We evaluated immune function in four MCD patients. These studies show: (1) a negative PPD skin test in 3/4 patients, (2) decreased IL-2 production in 3/4 patients, (3) decreased T cell colony formation in 3/4 patients, (4) decreased NK activity and NK cell number in 2/4 patients, (5) increased soluble IL-2 receptor in 4/4 patients, and (6) decreased CD4/CD8 ratio in 3/4 patients. These results show that MCD resembles, in several ways, acquired immunodeficiency syndrome (AIDS).

Meristem-specific gene expression directed by the promoter of the S-phase-specific gene, cyc07, in transgenic Arabidopsis

A genomic clone for the cyc07 gene, which is expressed specifically at the S phase during the cell cycle in synchronous cultures of periwinkle (Catharanthus roseus) cells, was isolated. Determination of the nucleotide sequence of the clone revealed that the cyc07 gene consists of seven exons separated by six introns. Genomic Southern analysis indicated that the cyc07 gene is present as a single copy per haploid genome in periwinkle. Expression of related genes was detected in a wide range of other plants. Transgenic Arabidopsis plants were generated that expressed the gene for beta-glucuronidase (GUS) under the control of the promoter of the cyc07 gene. The tissue-specific pattern of expression directed by the promoter was investigated by analysis of GUS activity. Histochemical tests demonstrated that 589 bp of the 5'-upstream sequence of the cyc07 gene could direct specifical expression of the GUS reporter gene in meristematic tissues in transgenic plants. The spatial pattern of expression directed by the promoter was closely correlated with meristematic activity and cell proliferation, suggesting an association between the function of the cyc07 gene and cell proliferation.

Limited effectiveness of FK506 administration for ongoing rejection in heterotopic rat heart transplantation

A comparison was made of the histological findings for myocardial tissue of heterotopic transplanted rat hearts administered with FK506. ACI rats were used as donors and Lewis rats as recipients. FK506 was used for 6 days except for group I (control group). Group II received 0.32 mg/kg/day of FK506 from the day of operation while group III was given the same dosage from the 4th day after transplantation. Group IV was given 1.28 mg/kg/day of the agent from the day of grafting and group V received the same dose from the 4th postoperative day. The graft survival time was longer for all groups given FK506, but was significantly longer only for groups administered with FK506 from the day of operation. Histological studies performed 10 and 20 days after transplantation showed that a moderate rejection was seen in about half of the grafts receiving FK506 from the 4th day after grafting. An ultrastructural study of these cases showed that infiltrating large lymphocytes still remained in the interstitial tissues and that the cytoplasmic organelles of the myocytes had been focally destroyed. These results suggest that, although FK506 suppressed any further rejection, the effect might be limited and the myocardial changes of the cardiac graft might persist even after administration for ongoing rejection.

Purification, characterization, primary structure, crystallization and preliminary crystallographic study of a serine proteinase from Streptomyces fradiae ATCC 14544

A proteinase having wide substrate specificity was isolated from Streptomyces fradiae ATCC 14544. This proteinase, which we propose to call SFase-2, was purified from the culture filtrate by S-Sepharose chromatography. The purified enzyme showed an apparent molecular mass of 19 kDa on SDS/PAGE. When synthetic peptides were used as substrates, SFase-2 showed broad substrate specificity. It also hydrolyzed keratin, elastin and collagen as proteinaceous substrates. It was completely inhibited by diisopropylfluorophosphate and chymostatin, but not by tosylphenylalaninechloromethane, tosyllysinechloromethane or EDTA, indicating that it can be classified as a serine proteinase. The matured protein sequence of SFase-2 was determined by a combination of amino acid sequencing and the DNA sequencing of the gene. SFase-2, consisting of 191 amino acids, is a novel proteinase. It showed 76% similarity in the amino acid sequence with Streptomyces griseus proteinase A [Johnson P. and Smillie L. B. (1974) FEBS Lett. 47, 1-6]. For insight into the three-dimensional structure of SFase-2, we obtained single crystals by the vapor diffusion method using sodium phosphate as a precipitant. These crystals belonged to the orthorhombic, space group P2(1)2(1)2(1) with cell dimensions a = 6.92 nm, b = 7.28 nm, c = 2.99 nm; one molecule was present in the asymmetric unit.

Correlation between clotting and collagen metabolism markers in rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory disease caused essentially by an immune-mediated mechanism. However, abnormalities of the clotting system have also been incriminated as having an important role in the pathogenesis of this disease. This study aims at assessing the clotting system and collagen metabolism alterations and the relationship between perturbances of the hemostatic pathway and the destructive and fibroproliferative processes in patients with rheumatoid arthritis. The coagulation system was evaluated by measuring thrombin-antithrombin III complex (TAT), prothrombin time (PT), activated partial thromboplastin time (APTT), and antithrombin III (AT-III). The fibrinolysis system was assessed by measuring fibrin degradation products (FDP), fibrinogen (FBG), alpha 2-antiplasmin (alpha 2-PI), D-dimer (DD) and plasmin-alpha 2-antiplasmin complex (PAP). As markers of collagen metabolism, the type III procollagen peptide (PIIIP) and the 7S domain of type IV collagen (7S-collagen) were determined. Blood concentrations of DD, PAP, TAT, PIIIP, and 7S-collagen were significantly higher in rheumatoid arthritis patients compared to controls. Serum levels of PIIIP were significantly correlated with PT, APTT, AT-III, FDP, and DD. 7S-collagen levels were inversely related to AT-III and FBG values. This study demonstrated the occurrence of a subclinical intravascular coagulation in rheumatoid arthritis and suggested the important role of blood coagulation in the alteration of the extracellular matrix metabolism in this disease.

Purification and some properties of alanine aminotransferase from Candida maltosa

Alanine aminotransferase (AlaAT; EC 2.6.1.2) was purified to homogeneity from Candida maltosa that was grown on L-alanine as the sole source of carbon and nitrogen. The enzyme has a molecular mass of 99kDa and consists of two subunits of equal molecular mass (52 kDa). Each subunit binds one mole of PLP. The enzyme has an isoelectric point of 5.3 and an optimum pH of 6.0-7.5. The spectroscopic profile and an inhibition experiment showed that both PLP and free-SH groups are directly involved in the enzymatic catalysis. In the N-terminal region of the enzyme, the consensus sequence (five amino acids) that commonly appears in mammalian and higher plant enzymes is present. Compared with mammalian enzyme, the Candida AlaAT is heat-sensitive and a little looser in substrate specificity, and its affinity towards L-alanine is high.

Prognosis of cervical spinal cord injury in correlation with magnetic resonance imaging

Magnetic resonance (MR) images of 18 patients with a cervical spinal cord injury were analysed for prognostic signs of paralysis. Serial MR images were obtained within 48 hours (acute stage), then 2 weeks (subacute stage) and an average of 12 months (range 6-24 months) after injury. The patterns of signal intensity in the acute stage were divided into two types, slightly-low/low (SL/L) type and slightly-low/high (SL/H) type on T1-weighted images (T1WI) and T2-weighted images (T2WI). The patterns in the subacute stage were divided into two types, high/high (H/H) type and normal/high (N/H) type on T1WI and T2WI. Six patients showed SL/L type in the acute stage and H/H type in the subacute stage. Five of the patients had a paralysis of grade A and one of grade B at admission which remained unchanged after treatment. One patient showed SL/H type in the acute stage and H/H type in the subacute stage. The patient had a paralysis of grade A that improved to no more than grade B. The remaining 11 patients showed SL/H type in the acute stage and N/H type in the subacute stage. Their paralysis was from grade B to D at admission and grade D or E at the follow up. The signal intensity of SL/L type in the acute stage and H/H type in the subacute stage are bad prognostic signs.

[Effect of a new anticancer drug, docetaxel (RP56976), on human leukemia cell lines]

The antitumor effect of a new derivative of taxol, docetaxel (RP56976), was examined in K562 human tumor system in vitro. K562 cells presenting a multidrug resistant phenotype showed cross resistance to docetaxel. However, the resistance levels of docetaxel in these cell lines were much lower than for adriamycin and vincristine. Flow cytometric analysis showed the accumulation of cells into G2/M phase after 18hrs. Wright-Giemsa staining showed a marked increase of metaphase population. Docetaxel was shown to promote the assembly of microtubule protein without GTP in vitro, but no inhibitory effect on DNA, RNA and protein synthesis. Moreover, topoisomerase activities were not affected by docetaxel. These results indicate that docetaxel acts as a strong mitotic inhibitor in cancer chemotherapy.

MR imaging of middle cerebral artery stenosis and occlusion: value of MR angiography

PURPOSE

To investigate the effectiveness of MR angiography in conjunction with spin-echo imaging for evaluating vascular patency in patients with middle cerebral artery (MCA) stenosis or occlusion.

METHODS

Seven patients with MCA stenosis or occlusion, verified with contrast angiography in five and correlated with transcranial Doppler sonography in two, were examined using two-dimensional and/or three-dimensional time-of-flight MR angiographic techniques as well as conventional spin-echo imaging.

RESULTS

Of the seven patients, six demonstrated basal ganglionic and/or cortical infarct in the MCA territory. Except one case with minimal stenosis immediately distal to the MCA origin, all six cases with either severe stenosis or occlusion of the main trunk of the MCA showed the absence of normal flow voids using spin-echo imaging in the sylvian fissure on the affected side. However, it was not possible to discriminate between stenosis and occlusion. Although different mechanisms (ie, flow-induced spin dephasing for the 2-D technique and progressive spin saturation for the 3-D technique) were predominantly responsible for the loss of signal through the area of stenosis, both the 2-D and 3-D MR angiograms clearly depicted the compromised flow of the MCA: a focal discontinuity with decreased vessel caliber corresponded to stenosis, and nonvisualization of distal MCA branches represented occlusion.

CONCLUSION

Either 2-D or 3-D time-of-flight MR angiography is a useful adjunct to conventional parenchymal spin-echo imaging for evaluating vascular patency in patients with MCA stenosis or occlusion, although it is important to recognize that each technique has a different basis for the loss of signal through the area of stenosis.

Detection of alcohol-tolerant hiochi bacteria by PCR

We report a sensitive and rapid method for detection of hiochi bacteria by PCR. This method involves the electrophoresis of amplified DNA. Nucleotide sequences of the spacer region between 16S and 23S rRNA genes of 11 Lactobacillus strains were identified by analysis of PCR products. Five primers were designed by analysis of similarities among these sequences. A single cell of Lactobacillus casei subsp. casei could be detected when purified genomic DNA was used as the template. When various cell concentrations of L. casei subsp. casei were added to 50 ml of pasteurized sake and the cells were recovered, the detection limit was about one cell. No discrete band was observed in electrophoresis after PCR when human, Escherichia coli, mycoplasma, Acholeplasma, yeast, or mold DNA was used as the template.

Acute effect of hydralazine administration on pulmonary artery hemodynamics in dogs with chronic heartworm disease

In an effort to better understand the role of vasodilators in the management of pulmonary hypertension associated with chronic heartworm disease (HWD), pulmonary hemodynamic measurements were obtained from 7 experimentally infected, anesthetized dogs before and after hydralazine administration (mean dose, 1.96 mg/kg of body weight). Five dogs were maintained on room air, while 2 were maintained on 100% oxygen during the hydralazine study. The hemodynamic effect of hydralazine in dogs with HWD was evaluated, using heart rate, cardiac index, mean pulmonary artery pressure, mean arterial pressure, total pulmonary resistance, total systemic resistance, total systemic resistance/total pulmonary resistance, left ventricular dP/dtmax, left ventricular end diastolic pressure, and left and right ventricular double products ([mean arterial pressure x heart rate] and [mean pulmonary artery pressure x heart rate], respectively). Responders were defined as those in which total pulmonary resistance decreased > or = 20% without an increase in mean pulmonary arterial pressure and in which heart rate increase was < or = 10%. Comparison was also made between maximal hemodynamic effect of hydralazine with that after 100% oxygen administration for 15 minutes to previously normoxemic dogs (n = 5). Significance was determined if P < 0.05, using the paired t-test. Hydralazine induced significant reductions in mean pulmonary and systemic arterial pressures and total pulmonary resistance, with no significant change in heart rate, cardiac index, total systemic resistance, left ventricular dP/dtmax, left ventricular end diastolic pressure, or right and left ventricular double products. Four (57%) of the 7 dogs studied were considered responders. Pretreatment cardiac index, mean pulmonary artery pressure, and total pulmonary resistance did not allow differentiation of responders from nonresponders.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between serum levels of interleukin-6 and thyroid hormone in children with acute respiratory infection

To determine whether monocyte-derived humoral factors such as tumor necrosis factor-alpha (TNF alpha), interleukin-1 beta (IL-1 beta), and IL-6 modulate serum thyroid hormone levels in infectious disorders, we measured serum levels of these monocyte-derived products, T3, T4, and C-reactive protein (CRP) in 59 out-patients with acute respiratory infection, aged 5 months to 15 yr (mean +/- SD, 5.7 +/- 4.2 yr). To minimize individual variation in their clinical and nutritional conditions, we selected out-patients with fever lasting for at least 3 days who had no severe disturbance of food intake. Serum T3 concentrations tended to be low in these subjects; 3 (5.1%) had levels below 1.2 nmol/L, L, and 13 (22.0%) had levels below 1.5 nmol/L. Serum T3 levels in 22 patients with elevated IL-6 (> 15 pg/mL) were significantly lower than those in 19 patients with normal IL-6 (< or = 5 pg/mL; T3, 1.7 +/- 0.4 vs. 2.2 +/- 0.6 nmol/L; P < 0.05). The serum IL-6 concentration was correlated inversely with the serum T3 level (r = -0.324; P = 0.012) as well as the T3/T4 ratio (r = -0.279; P = 0.032). Furthermore, a significant negative correlation was observed between CRP (induced mainly by IL-6) and T3 (r = -0.408; P = 0.001) or the T3/T4 ratio (r = 0.302; P = 0.020). On the other hand, TNF alpha was measurable in only 9 of 59 patients, and there was no correlation between TNF alpha and levels of thyroid hormone, CRP, or IL-6. Serum IL-1 beta was weakly detected in only 1 patient. On follow-up study of 10 of these patients, the serum T3 and T3/T4 ratio increased significantly with a reciprocal decrease in IL-6 and CRP during convalescence. No remarkable change in the serum T4 level was observed in our study. Our data suggest that the euthyroid sick syndrome is relatively common in children with acute respiratory infection, and IL-6 appears to mediate this syndrome in infectious disorders.