The IgG1/G2 subclass shift--a sensitive, tissue non-specific marker for malignancy. Diagnostic performance with squamous cell carcinoma of the head and neck

A significant decrease in %IgG1 accompanied by an increase in %IgG2 in total serum IgG has been previously reported as a highly sensitive marker for detecting early stages of carcinomas of various localizations. Here we investigated the question as to whether this phenomenon is also observed in sera of patients with squamous cell carcinoma of the head-neck region (SCC-HN), and to evaluate its diagnostic performance in the post-operative monitoring. Using quantitative affinity chromatography, serum concentrations of IgG1, IgG2 and total IgG were determined in 81 patients with different stages of primary and untreated SCC-HN, in 51 SCC-HN patients in post-therapeutical follow up, and in 33 patients with organ matched benign diseases. The data were compared with a total of 174 healthy controls. It was found that (i) 105 SCC-HN patients exhibited a mean value of 56.0 +/- 0.7% IgG1, which likewise differed from healthy controls (63.2 +/- 0.5) and benign diseases (61.5 +/- 1.0) with P < 0.0005, (ii) sensitivities and specificities for discriminating primary malignancies from healthy controls were 70 and 74% respectively, and from benign diseases 65 and 76%, (iii) highest sensitivities and specificities were observed with post-therapeutic cases suffering from tumour recurrence (88% and 75%) or patients with distant metastases (87% and 86%), (iv) apparently tumour-free post-therapeutic patients showed a mean %IgG1 not different from the normal value. The decrease in %IgG1 accompanied by increased %IgG2 is an efficient, sensitive and early marker of SCC-HN, which appears particularly useful for the post-therapeutic monitoring.

Energy and substrate metabolism in patients with active Crohn's disease

The aim of the study was to evaluate the possible contribution of changes in energy metabolism and substrate oxidation rates to malnutrition in Crohn's disease and to assess the effect of enteral nutrition on these parameters. Energy metabolism was evaluated by indirect calorimetry in 32 patients with active Crohn's disease and 19 age- and sex-matched healthy individuals. Measurements were done in the postabsorptive state. Seven out of 32 patients received enteral nutrition via a nasogastric tube. In these patients, resting energy metabolism was determined at d 0 (postabsorptive), 7, 14 (during full enteral nutrition) and 15 (postabsorptive). Resting energy expenditure was not significantly different between patients and controls, whereas the respiratory quotient (RQ) was lower in patients (0.78 +/- 0.05 vs. 0.86 +/- 0.05; P < 0.05). During enteral nutrition in 7 patients with Crohn's disease, the RQ increased on d 7 compared with d 0 and remained high even after cessation of enteral nutrition (d 0, 0.78 +/- 0.03; d 7, 0.91 +/- 0.04; d 15, 0. 84 +/- 0.05; P < 0.05; d 7 and 15 vs. d 0). No effects of enteral nutrition on resting energy expenditure were found. Active Crohn's disease is associated with changes in substrate metabolism that resemble a starvation pattern. These changes appear not to be specific to Crohn's disease but to malnutrition and are readily reversed by enteral nutrition. Enteral nutrition did not affect resting energy expenditure. Wasting is a consequence of malnutrition but not of hypermetabolism in Crohn's disease.

Action of aprotinin in myocardial ischemia - an investigation using a plasma-free model

BACKGROUND

The protease inhibitor aprotinin has been reported to have an anti-ischemic effect on left-ventricular myocardium in patients undergoing cardiopulmonary bypass operation. To examine the anti-ischemic properties beside its antifibrinolytic and inhibitory action on the kallikrein-bradykinin system, we investigated this substance in buffer-perfused rat hearts.

METHODS

24 isolated isovolumically contracting rat hearts received a 10-minute infusion of either 10000 units aprotinin or pure saline followed by 30 minutes of no-flow global ischemia and 45 minutes of reperfusion. Hemodynamics, high-energy phosphates, and troponin T as molecular marker of cardiac injury were studied.

RESULTS

During 15 minutes of reperfusion steady state function was identical in both groups, with a recovery of the developed left-ventricular pressure to 81.9+/-1.5% after protease inhibition and 83.0+/-2.6% in the controls. Coronary flow, myocardial oxygen consumption, and contractile reserve after maximum Ca++ stimulation were also identical. High-energy phosphates were comparably reduced in both groups (adenine nucleotides: 3.1+/-0.3 micromol/g ww after aprotinin vs. controls 2.7+/-0.4 micromol/g ww and creatine phosphate: 6.5+/-0.9 micromol/g ww vs. controls 4.7+/-1.1 micromol/g ww). However, release of the cardiac specific marker troponin T was lower after ischemia at several measurements (p<0.05). The total release of troponin T was 44+/-10 ng in the aprotinin treated hearts vs. 90+/-17 ng in the postischemic control hearts (p<0.05).

CONCLUSIONS

The findings demonstrate that aprotinin in a moderate dose is effective in reducing postischemic troponin release in a non-blood perfused system. Measurement of myocardial high-energy phosphates after aprotinin use was performed for the first time and indicates that not a reduction in severity of direct myocardial ischemic intensity but a beneficial action on processes causing release of troponin is the mode of action of this effect.

Ectopic expression of prion protein (PrP) in T lymphocytes or hepatocytes of PrP knockout mice is insufficient to sustain prion replication

The cellular form of the Prion protein (PrPC) is necessary for prion replication in mice. To determine whether it is also sufficient, we expressed PrP under the control of various cell- or tissue-specific regulatory elements in PrP knockout mice. The interferon regulatory factor-1 promoter/Emu enhancer led to high PrP levels in the spleen and low PrP levels in the brain. Following i.p. scrapie inoculation, high prion titers were found in the spleen but not in the brain at 2 weeks and 6 months, showing that the lymphoreticular system by itself is competent to replicate prions. PrP expression directed by the Lck promoter resulted in high PrP levels on T lymphocytes only but, surprisingly, did not allow prion replication in the thymus, spleen, or brain following i.p. inoculation. A third transgenic line, which expressed PrP in the liver under the control of the albumin promoter/enhancer-albeit at low levels-also failed to replicate prions. These results show that expression of PrP alone is not sufficient to sustain prion replication and suggest that additional components are needed.

Evidence for kinetic inhomogeneity in the curing of epoxy using the near-infrared multispectral imaging technique

The kinetics of curing of an epoxy resin by amine was studied using a near-infrared (NIR) multispectral imaging spectrometer. This imaging spectrometer is capable of sensitively and rapidly recording NIR spectral images of a sample because it was constructed with an acousto-optic tunable filter and an InGaAs focal plane array NIR camera. The high sensitivity and fast scanning ability of the spectrometer make it suitable for kinetic determination of fast reactions. Additionally, it has features that conventional NIR spectrometers cannot offer, namely, its ability to provide kinetic information at different positions within a sample. Furthermore, the high spatial resolution and sensitivity of the InGaAs camera make it possible to determine the kinetics from data collected by a single pixel in the camera. The kinetics of curing of epoxy by amine, determined by this multispectral imaging instrument, show that the reaction rates within the sample are very inhomogeneous. Because of this kinetic inhomogeneity, differences in the degrees of cure at different positions within the sample can be as high as 37% when data from only a single pixel were used for calculation. The inhomogeneity was not be observed if an average of a large number of pixels were used.

The prediction of failure of the stem in THR by measurement of early migration using EBRA-FCA. Einzel-Bild-Roentgen-Analyse-femoral component analysis

We report the ten-year results for three designs of stem in 240 total hip replacements, for which subsidence had been measured on plain radiographs at regular intervals. Accurate migration patterns could be determined by the method of Einzel-Bild-Roentgen-Analyse-femoral component analysis (EBRA-FCA) for 158 hips (66%). Of these, 108 stems (68%) remained stable throughout, and five (3%) started to migrate after a median of 54 months. Initial migration of at least 1 mm was seen in 45 stems (29%) during the first two years, but these then became stable. We revised 17 stems for aseptic loosening, and 12 for other reasons. Revision for aseptic loosening could be predicted by EBRA-FCA with a sensitivity of 69%, a specificity of 80%, and an accuracy of 79% by the use of a threshold of subsidence of 1.5 mm during the first two years. Similar observations over a five-year period allowed the long-term outcome to be predicted with an accuracy of 91%. We discuss the importance of four different patterns of subsidence and confirm that the early measurement of migration by a reasonably accurate method can help to predict long-term outcome. Such methods should be used to evaluate new and modified designs of prosthesis.

Complementation of the fol2 deletion in Saccharomyces cerevisiae by human and Escherichia coli genes encoding GTP cyclohydrolase I

Saccharomyces cerevisiae is so far the only organism where a knock-out mutant in the gene encoding GTP cyclohydrolase I (FOL2) has been obtained. GTP cyclohydrolase I controls the de novo biosynthetic pathway of tetrahydrobiopterin and folic acid. Since deletion of yeast FOL2 leads to a recessive auxotrophy for folinic acid, we used a yeast fol2Delta mutant for an in vivo functional assay of heterologous GTP cyclohydrolases I. We show that the GTP cyclohydrolase I, encoded either by the E. coli folE gene or by the human cDNA, complements the yeast fol2Delta mutation by restoring folate prototrophy. Furthermore the folE-3x allele of the E. coli gene, carrying three base substitutions, failed to complement the yeast fol2Delta defect. This allele behaved as a negative semidominant to the wild type folE and, when overexpressed, completely abolished complementation of fol2Delta by folE. Thus, the yeast fol2 null mutant is a suitable system to characterize mutations in genes encoding GTP cyclohydrolase I.

Antioxidant status in patients with acute respiratory distress syndrome

OBJECTIVES

Reactive oxygen species (ROS) have been implicated in the pathophysiology of ARDS. We investigated the pattern of antioxidants in plasma and ROS production by neutrophils in patients with ARDS over 6 days.

DESIGN

Observational study. Blood samples were taken when the diagnosis was made (D0) and after 3 (D3) and 6 days (D6) during therapy.

SETTING

Intensive care units at a University Hospital.

PATIENTS

Eight patients with ARDS were investigated, 17 healthy volunteers served as controls.

MEASUREMENTS AND RESULTS

Plasma levels of ascorbate, alpha-tocopherol, retinol, beta-carotene, selenium and lipid peroxidation products (MDA) were determined and the activities of the antioxidative enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) in erythrocytes were measured. In addition, ROS production (superoxide anion and hydrogen peroxide) in activated neutrophils was assessed. Plasma levels of alpha-tocopherol, ascorbate, beta-carotene and selenium were reduced from the onset of illness. MDA plasma levels were increased throughout the illness. ROS generation from neutrophils was normal on D0 and decreased to D6 in ARDS patients.

CONCLUSION

The antioxidative system is severely compromised in patients with ARDS. Plasma levels of alpha-tocopherol, ascorbate, beta-carotene and selenium are decreased. Elevated MDA levels provide further evidence of massive oxidative stress. The routine replacement of micronutrients according to recommended daily allowances was inadequate to compensate for the increased requirements.

The designer cytokine hyper-interleukin-6 is a potent activator of STAT3-dependent gene transcription in vivo and in vitro

Interleukin-6 (IL-6) triggers pivotal pathways in vivo. The designer protein hyper-IL-6 (H-IL-6) fuses the soluble IL-6 receptor (sIL-6R) through an intermediate linker with IL-6. The intracellular pathways that are triggered by H-IL-6 are not defined yet. Therefore, we studied the molecular mechanisms leading to H-IL-6-dependent gene activation. H-IL-6 stimulates haptoglobin mRNA expression in HepG2 cells, which is transcriptionally mediated as assessed by run-off experiments. The increase in haptoglobin gene transcription correlates with higher nuclear translocation of tyrosine-phosphorylated STAT3 and its DNA binding. As H-IL-6 stimulates STAT3-dependent gene transcription, we compared the molecular mechanism between IL-6 and H-IL-6. Transfection experiments were performed with a STAT3-dependent luciferase construct. The same amount of H-IL-6 stimulated luciferase activity faster, stronger, and for a longer period of time. Dose response experiments showed that a 10-fold lower dose of H-IL-6 stimulated STAT3-dependent gene transcription comparable with the higher amount of IL-6. Cotransfection with the gp80 and/or gp130 receptor revealed that the effect of H-IL-6 on STAT3-dependent gene transcription is restricted to the gp80/gp130 receptor ratio. High amounts of gp130 increased and high amounts of gp80 decreased the effect on H-IL-6-dependent gene transcription. To investigate the in vivo effect of H-IL-6 on gene transcription in the liver, H-IL-6 and IL-6 were injected into C3H mice. H-IL-6 was at least 10-fold more effective in stimulating the DNA binding and nuclear translocation of STAT3, which enhances haptoglobin mRNA and protein expression. Thus H-IL-6 stimulates STAT3-dependent gene transcription in liver cells in vitro and in vivo at least 10-fold more effectively than IL-6. Our results provide evidence that H-IL-6 is a promising designer protein for therapeutic intervention during different pathophysiological conditions also in humans.

Divalent cation block of inward currents and low-affinity K+ uptake in Saccharomyces cerevisiae

We have used the patch clamp technique to characterize whole-cell currents in spheroplasts isolated from a trk1Delta trk2Delta strain of Saccharomyces cerevisiae which lacks high- and moderate-affinity K+ uptake capacity. In solutions in which extracellular divalent cation concentrations were 0.1 mM, cells exhibited a large inward current. This current was not the result of increasing leak between the glass pipette and membrane, as there was no effect on the outward current. The inward current comprised both instantaneous and time-dependent components. The magnitude of the inward current increased with increasing extracellular K+ and negative membrane potential but was insensitive to extracellular anions. Replacing extracellular K+ with Rb+, Cs+, or Na+ only slightly modulated the magnitude of the inward current, whereas replacement with Li+ reduced the inward current by approximately 50%, and tetraethylammonium (TEA+) and choline were relatively impermeant. The inward current was blocked by extracellular Ca2+ and Mg2+ with apparent Kis (at -140 mV) of 363 +/- 78 and 96 +/- 14 microM, respectively. Furthermore, decreasing cytosolic K+ increased the magnitude of the inward current independently of the electrochemical driving force for K+ influx, consistent with regulation of the inward current by cytosolic K+. Uptake of 86Rb+ by intact trk1Delta trk2Delta cells was inhibited by extracellular Ca2+ with a Ki within the range observed for the inward current. Furthermore, increasing extracellular Ca2+ from 0.1 to 20 mM significantly inhibited the growth of these cells. These results are consistent with those of the patch clamp experiments in suggesting that low-affinity uptake of alkali cations in yeast is mediated by a transport system sensitive to divalent cations.

Is speech arrest during wada testing a valid method for determining hemispheric representation of language?

BACKGROUND AND OBJECTIVE

The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization.

METHODS

The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed.

RESULTS

There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r =.35, p =.12) or FMRI language laterality score (r =.32, p =.16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods.

CONCLUSION

Duration of speech arrest during Wada testing is not a valid measure of language dominance.

[Carcinoid tumors of the lung and asbestos. Clinical aspects for insurance medicine]

Lung dust analyses were performed on tumor-free lung tissue from surgical samples of 28 carcinoid tumors. The measured levels in one surgical sample may easily be correlated with the increased asbestos load of the lung due to the patients' occupation as stone mason. No evidence supporting the correlation of increased chronic asbestos load of the lungs and the development of typical carcinoid tumors of the lung was found.

Use of the restricted academic task in ADHD dose-response relationships

Behavioral assessment techniques have been shown to make a significant contribution in the evaluation of stimulant medication response in children with attention-deficit/hyperactivity disorder. This article examines the role of a behavioral measure consisting of standardized observation of a child while he or she performs an academic-like task (Restricted Academic Task). This technique is reliable and valid for repeated administrations across medication dosages and placebo. It can assist in optimizing medication dosage for individual children, given its sensitivity to dosage effects. It also allows the capture of medication-related changes in an area of functioning that is not directly assessed by parent and teacher judgments and ratings. In this way the Restricted Academic Task may have greater ecological validity than the results of other, more traditional in-clinic measures. Finally, given the idiosyncratic nature of stimulant medication effects on individual children, it contributes to the explication of a specific child's behavioral dose-response relationship.

In Vivo and In Vitro Activities of the gp130-Stimulating Designer Cytokine Hyper-IL-6

IL-6 is a multifactorial cytokine mediating acute inflammatory responses in the liver. When IL-6 binds to a specific receptor (IL-6R), the IL-6/IL-6R complex associates with the signal transducer gp130, initiating intracellular signaling. A soluble form of the IL-6R (sIL-6R) renders target cells sensitive to IL-6 that do not express the IL-6R on their surfaces. A designer cytokine, termed Hyper-IL-6, consisting of IL-6 covalently linked to the sIL-6R was fully active on gp130-expressing cells at 100- to 1000-fold lower concentrations than unlinked IL-6 and IL-6R. Mice were injected i.p. with Hyper-IL-6 or IL-6. Upon injection of Hyper-IL-6 into mice, the acute phase response, as measured by haptoglobin mRNA expression in the liver, was markedly increased and lasted significantly longer compared with that in mice injected with a 10-fold higher dose of IL-6 alone. On human hepatoma cells, Hyper-IL-6 caused similar effects, indicating that the longer lasting response to the fusion protein could not only be explained by the longer plasma half-life of the fusion protein. Experiments using iodinated IL-6 and Hyper-IL-6 revealed that Hyper-IL-6 bound with high affinity to gp130 and was less efficiently internalized. This effect might explain the longer lasting activity of this protein on cells. The highly active IL-6/sIL-6R designer protein might be of significant clinical importance for the stimulation of cells that are more responsive to the IL-6/sIL-6R complex than to IL-6 alone. Such cells include hemopoietic progenitor cells and hepatocytes.

In vivo and in vitro activities of the gp130-stimulating designer cytokine Hyper-IL-6

IL-6 is a multifactorial cytokine mediating acute inflammatory responses in the liver. When IL-6 binds to a specific receptor (IL-6R), the IL-6/IL-6R complex associates with the signal transducer gp130, initiating intracellular signaling. A soluble form of the IL-6R (sIL-6R) renders target cells sensitive to IL-6 that do not express the IL-6R on their surfaces. A designer cytokine, termed Hyper-IL-6, consisting of IL-6 covalently linked to the sIL-6R was fully active on gp130-expressing cells at 100- to 1000-fold lower concentrations than unlinked IL-6 and IL-6R. Mice were injected i.p. with Hyper-IL-6 or IL-6. Upon injection of Hyper-IL-6 into mice, the acute phase response, as measured by haptoglobin mRNA expression in the liver, was markedly increased and lasted significantly longer compared with that in mice injected with a 10-fold higher dose of IL-6 alone. On human hepatoma cells, Hyper-IL-6 caused similar effects, indicating that the longer lasting response to the fusion protein could not only be explained by the longer plasma half-life of the fusion protein. Experiments using iodinated IL-6 and Hyper-IL-6 revealed that Hyper-IL-6 bound with high affinity to gp130 and was less efficiently internalized. This effect might explain the longer lasting activity of this protein on cells. The highly active IL-6/sIL-6R designer protein might be of significant clinical importance for the stimulation of cells that are more responsive to the IL-6/sIL-6R complex than to IL-6 alone. Such cells include hemopoietic progenitor cells and hepatocytes.

Human IgA- and IgM-secreting intestinal plasma cells carry heavily mutated VH region genes

Single IgA- or IgM-secreting plasma cells were isolated from histological sections of human jejunum and terminal ileum, and Ig heavy chain variable (VH) region genes were amplified and sequenced. Taken together, 62 of 63 cells analyzed harbored somatically mutated VH region genes, indicating that the vast majority of both IgA- and IgM-secreting intestinal plasma cells derive from germinal center B cells. On average, rearranged VH genes of IgA- and IgM-secreting plasma cells showed a mutation frequency of 9.0 % and 8.5 %, respectively, which exceeds the level of somatic mutation of V region genes carried by human memory B cells. Moreover, we detected deletions or insertions in the complementarity-determining regions of 5 of the 58 functional VH region genes analyzed, suggesting that these alterations may contribute to the diversification of the human antibody repertoire in the course of an immune reaction.

A 2-year longitudinal study of swimming navigation in mice devoid of the prion protein: no evidence for neurological anomalies or spatial learning impairments

Uncontrolled accumulation of a conformationally distorted protein (PrP(Sc)) is supposed to be the pathological process leading to spongiform encephalopathy. Targeted disruptions of the Prn-P gene in the mouse have resulted in animals that did not show anomalies in spatial and avoidance learning and were resistant to experimental infections. However, another Prn-P knockout mouse was reported to show ataxia and Purkinje cell degeneration developing after 70 weeks of age. In this study the initial observations are confirmed on swimming navigation of PrP-null mutant mice using an enlarged sample of 58 mice. A representative subsample of 16 mice was then followed up for their ability of swimming navigation up to an age of two years (104 weeks). Surviving PrP-null mutants (n = 4) and controls (n = 6) did not differ in any measure, nor were there indications of ataxia and Purkinje cell degeneration. It was concluded that the PrP-knockout mice used by Büeler et al. were probably normal with respect to aging processes and that resistance to scrapie is not necessarily paid for by late neuronal degeneration. The reasons for the discrepancy between different knockout experiments require experimental clarification, however.

The membrane proximal cytokine receptor domain of the human interleukin-6 receptor is sufficient for ligand binding but not for gp130 association

Interleukin-6 (IL-6) belongs to the family of the "four-helix bundle" cytokines. The extracellular parts of their receptors consist of several Ig- and fibronectin type III-like domains. Characteristic of these receptors is a cytokine-binding module consisting of two such fibronectin domains defined by a set of four conserved cysteines and a tryptophan-serine-X-tryptophan-serine (WSXWS) sequence motif. On target cells, IL-6 binds to a specific IL-6 receptor (IL-6R), and the complex of IL-6.IL-6R associates with the signal transducing protein gp130. The IL-6R consists of three extracellular domains. The NH2-terminal Ig-like domain is not needed for ligand binding and signal initiation. Here we have investigated the properties and functional role of the third membrane proximal domain. The protein can be efficiently expressed in bacteria, and the refolded domain is shown to be sufficient for IL-6 binding. When complexed with IL-6, however, it fails to associate with the gp130 protein. Since the second and the third domain together with IL-6 can bind to gp130 and induce signaling, our data demonstrate the ligand binding function of the third domain and point to an important role of the second domain in complex formation with gp130 and signaling.