Alternaria alternata NADP-dependent mannitol dehydrogenase is an important fungal allergen

BACKGROUND

Alternaria alternata is one of the most important allergenic fungi worldwide. Mannitol dehydrogenase (MtDH) has previously been shown to be a major allergen of Cladosporium herbarum and cross-reactivity has been demonstrated for several fungal allergens.

OBJECTIVE

The present study's objective was to clone the MtDH from an A. alternata cDNA library, express and purify the recombinant non-fusion protein and test its IgE-binding properties. Methods A cDNA library prepared from A. alternata hyphae and spores was screened for mannitol dehydrogenase by DNA hybridization with the radioactively labelled C. herbarum homologue as a probe. The resulting clone was sequenced and heterologously expressed in Escherichia coli as a recombinant non-fusion protein, which was purified to homogeneity and analysed for its IgE-binding capacity.

RESULTS

The coding sequence of the full-length cDNA clone comprises 798 bp encoding a protein with a molecular mass of 28.6 kDa and a predicted pI of 5.88. Protein sequence analysis revealed an identity of 75% and a homology of 86% between the MtDHs of A. alternata and C. herbarum. The functional mannitol dehydrogenase was expressed in the E. coli strain BL21(DE3) transformed with the vector pMW172 and purified to homogeneity. The enzyme catalyses the NADPH-dependent conversion of d-fructose to d-mannitol. In IgE-ELISA and immunoblots, MtDH is recognized by 41% of A. alternata-allergic patients. In vivo immunoreactivity of the recombinant MtDH was verified by skin prick testing. Finally, inhibition-ELISA experiments confirmed cross-reactivity between the MtDHs of A. alternata and C. herbarum.

CONCLUSION

Mannitol dehydrogenase (Alt a 8) represents an important new allergen of the ascomycete A. alternata that might be suitable for improving diagnostic and therapeutic procedures.

NADP-dependent mannitol dehydrogenase, a major allergen of Cladosporium herbarum

Cladosporium herbarum is an important allergenic fungal species that has been reported to cause allergic diseases in nearly all climatic zones. 5-30% of the allergic population displays IgE antibodies against molds. Sensitization to Cladosporium has often been associated with severe asthma and less frequently with chronic urticaria and atopic eczema. However, no dominant major allergen of this species has been found so far. We present cloning, production, and characterization of NADP-dependent mannitol dehydrogenase of C. herbarum (Cla h 8) and show that this protein is a major allergen that is recognized by IgE antibodies of approximately 57% of all Cladosporium allergic patients. This is the highest percentage of patients reacting with any Cladosporium allergen characterized so far. Cla h 8 was purified to homogeneity by standard chromatographic methods, and both N-terminal and internal amino acid sequences of protein fragments were determined. Enzymatic analysis of the purified natural protein revealed that this allergen represents a NADP-dependent mannitol dehydrogenase that interconverts mannitol and d-fructose. It is a soluble, non-glycosylated cytoplasmic protein. Two-dimensional protein analysis indicated that mannitol dehydrogenase is present as a single isoform. The cDNA encoding Cla h 8 was cloned from a lambda-ZAP library constructed from hyphae and spores. The recombinant non-fusion protein was expressed in Escherichia coli and purified to homogeneity. Its immunological and biochemical identity with the natural protein was shown by enzyme activity tests, CD spectroscopy, IgE immunoblots with sera of patients, and by skin prick testing of Cladosporium allergic patients. This protein therefore is a new major allergen of C. herbarum.

Comparing filtered backprojection and ordered-subsets expectation maximization for small-lesion detection and localization in 67Ga SPECT

Iterative reconstruction of SPECT images has recently become clinically available as an alternative to filtered backprojection (FBP). However, there is conflicting evidence on whether iterative reconstruction, such as with the ordered-subsets expectation maximization (OSEM) algorithm, improves diagnostic performance over FBP. The study objective was to determine if the detection and localization of small lesions in simulated thoracic gallium SPECT images are better with OSEM reconstruction than with FBP, both with and without attenuation correction (AC).

METHODS

Images were simulated using an analytic projector acting on the mathematic cardiac torso computer phantom. Perfect scatter rejection was assumed. Lesion detection accuracy was assessed using localization receiver operating characteristic methodology. The images were read by 5 nuclear medicine physicians. For each reconstruction strategy and for each observer, data were collected in 2 viewing sessions of 100 images. Two-way ANOVA and, when indicated, the Scheffé multiple comparisons test were applied to check for significant differences.

RESULTS

Little difference in the accuracy of detection or localization was seen between FBP with and without AC. OSEM with AC extended the contrast range for accurate lesion detection and localization over that of the other methods investigated. Without AC, no significant difference between OSEM and FBP reconstruction was detected.

CONCLUSION

OSEM with AC may improve the detection and localization of thoracic gallium-labeled lesions over FBP reconstruction.

[Psychological and psychodynamic education of physicians]

Not every Doctor needs a training in the doctor-patient relationship and in the knowledge of the psychodynamics issues of his patients. But it is a must for the doctors who treat and look after their patients. The people in charge of this training should consider the importance of the unconscious and consequently of the psychoanalytical dimension. The resistances against the psychodynamic approach by the reduction to the common sens, the use of the parallel medicines or the systemic and cognitive approaches. The need and desire of this type of formation in relation to the professional personality of the Doctor.

Spreading properties of dimyristoyl phosphatidylcholine at the air/water interface

The spreading behavior of bulk lipid crystals and lipid dispersed in water has been investigated for dimyristoyl phosphatidylcholine at the air/water interface. The stable surface pressures reached with dispersed lipid were found to increase with lipid concentration up to a concentration of approximately 1.2 mg ml-1 where the spreading pressure approached 45 mN m-1, the value for excess lipid crystals placed on the surface (at 30.5 degrees C). These low surface pressures obtained with dispersions are attributed to the existence of 'pre-equilibria': surface pressures that appear steady because of the extremely slow approach to final equilibrium. Attainment of this pre-equilibrium condition usually takes about 20 h, whereas bulk crystals held at the surface generated a high and steady surface pressure within about 1 h. Hydration of the bulk lipid slows down the spreading rate, but does not affect the final surface pressure.

Dietary supplementation with omega-3 fatty acids prolongs platelet survival in hyperlipidemic patients with atherosclerosis

Enhanced dietary omega-3 fatty acid consumption is thought to be associated with a reduced incidence of atherothrombotic disorders. This effect may be mediated in part through suppression of in vivo platelet activity by omega-3 fatty acids. We observed that platelet survival, a sensitive indicator of in vivo platelet activity was prolonged from 6.4 +/- 1.5 days to 7.7 +/- 1.4 days by moderate amounts of dietary omega-3 fatty acid supplementation for 6 weeks in a group of hyperlipidemic patients with preexisting, established atherothrombotic disorders. This effect on platelet survival was associated with a decrease in platelet arachidonic acid levels from 26.7 +/- 3.5% to 20.9% +/- 2.5% and a rise in platelet eicosapentaenoic and docosahexaenoic acid measurements from essentially undetectable to 2.8% +/- 1.6% and 1.9% +/- 1.0%. Plasma total cholesterol, low-density lipoprotein cholesterol, and serum apolipoprotein B levels rose significantly during the omega-3 fatty acid supplementation period. Platelet aggregation did not change. This study demonstrates that a modest amount of dietary omega-3 fatty acid supplementation can significantly effect in vivo platelet activity in a population at high risk for recurrent atherothrombotic disorders.

Acalculous cholecystitis: a case with variable cholescintigram

A 62-yr-old man with acalculous cholecystitis is presented. At different stages of his disease his cholescintigram was abnormal and then normal. The case demonstrates the variations of the cholescintigram that may occur during the disease and illustrates the difficulties that may be encountered in making the diagnosis.

Simple, rapid thyroid function testing with 99mTc-pertechnetate thyroid uptake ratio and neck/thigh ratio

To avoid the technical difficulties and errors inherent in the measurement of early thyroid uptake of 99mTcO4-,techniques which are independent of absolute uptake, neck extrathyroidal background and dose standards were evaluated in a series of 108 patients. After intravenous injection of 2 mCi 99mTcO4-, radioactivity was recorded over the neck and thigh. Thyroid uptake ratios were calculated as the ratios of activity over the neck at two times. A neck/thigh ratio was calculated from the recorded activities at 15 min after injection. Examination of these parameters showed that a combination of the 15 min neck/thigh ratio and the 10'/2' thyroid uptake ratio best served to discriminate thyroid function: 92% of hyperthyroid cases were correctly identified by a neck/thigh ratio above 4.7 and 95% of hypothyroid cases were identified by the combination of a neck/thigh ratio below 3 and a 10'/2' thyroid uptake ratio below 1. Correct classification of euthyroidism was 84% but with the exclusion of patients previously treated with 131I, this rose to 91%. The accuracy of the 99mTc procedure is comparable to that of the standard 24 hr 131I uptake run concurrently in this series and duplicates the accuracy of computer assisted determinations of absolute thyroid 99mTcO4- uptakes. The procedure provides a convenient method for the evaluation of thyroid function as an accompaniment to 99mTcO4- thyroid imaging.

[Suicide risk and care of suicide attempters]

Starting from the notion of suicidal risk and a critique of its usage, it is possible to distinguish groups whose suicidal risk is particularly high. The suicidal group-composed of persons who have already attempted to commit suicide once-is in this paper the subject of general considerations as well as personal research. The latter shows that it is still difficult to detect those persons who are about to commit suicide and that tell-tale signs-be they clinical or resulting from tests-are still not very reliable. The difficulties encountered by secondary prevention are made obvious by two pieces of research done on the taking in charge of suicide-prone persons in a university general hospital. the timely recognition of the pre-suicidal syndrome and of the self-denial syndrome is very important for suicide prevention. Self-depreciation, and consequently the narcissistic blow is, as are the aggression phenomena, one of the psychological cores which lead to an act of suicide. Medical attitudes concerning the suicidal person are analyzed, and the difficulty in the psychotherapeutic relationship is stressed. Pratical considerations on the psychotherapeutic approach to the suicidal person close up the article.

The psychotherapy of the psychosomatic patient

On the basis of a relatively restricted definition of psychotherapy, the authors describe some of the reasons why psychotherapy is rather seldom used for psychosomatic patients, on an individual or a group basis. Some details are then given about two other kinds of treatment which contain some elements of psychotherapy, and which have been developed in Lausanne as a consequence of the analysis of the early transactions between the psychosomatic patient and his attendants: (1) a bio-feedback method, whose technical aspect is used as a tool towards a more global approach, through encouraging insight and verbalization on the part of the patient; (2) an interdisciplinary approach by physiotherapists, psychiatrists and somaticians, working together in different modalities, adapted to the different cases.

Uptake of bone imaging agents by diffuse pulmonary metastatic calcification

Three cases of diffuse lung uptake of the bone scanning agent 99mTc diphosphonate, which appears to reflect metastatic pulmonary calcification, are described. Each patient had hypercalcemia and renal failure. Clinical features common to patients with this scan pattern were ascertained from a review of the literature. Renal failure was present in all, and the majority have had hypercalcemia. The bone scan may prove to be a valuable adjunct to the diagnosis of metastatic pulmonary calcification; this characteristic pattern should be more widely appreciated.

A sensitive radioenzymatic assay for glycerol and acylglycerols

A sensitive radioenzymatic assay for glycerol and acylglycerols is described. The assay depends on the quantitative phosphorylation of glycerol to glycerophosphate by glycerol kinase using [gamma-32P]ATP as a substrate. The 32P content of the formed glycerophosphate is determined and gives a measure of the original glycerol content. Acylglycerols can be determined by prior hydrolysis to glycerol. The assay is sensitive to about 0.1 nmol of glycerol and can be extended to 100 nmol. The assay can be applied to the determination of acylglycerols separated by thin-layer chromatography in amounts as low as 0.5 nmol. The assay is particularly useful in the determination of the specific activity of 14C- or 3H-labeled glycerol moeities.

Stimulation by serum of 32P incorporation into the phospholipids of Ehrlich ascites cells

Ehrlich ascites cells adapted for suspension culture were incubated with 32PO43- in a Krebs-Ringer-HEPES (N-2-hydroxyethyl-piperazine-N'-2-ethanesulfonate) buffer with or without 5% calf serum. Specific activity was determined for cellular [gamma-32P]ATP, total phospholipids, and the individual phospholipids fractionated by two-dimensional thin-layer chromatography. Serum stimulated the incorporation of 32P into the phosphatides with a 2-3-fold increase in specific activity of phosphatidylcholine and phosphatidylethanolamine. Phosphatidylinositol showed a moderate increase. Phosphatidic acid showed an increase that could be accounted for by a parallel small increase in the specific activity of precursor [gamma-32P]-ATP. The effect os serum could be discerned as early as 10 min after its addition. Complete inhibition of protein synthesis by cycloheximide or puromycin did not interfere with the serum stimulation of 32P incorporation into lipids, indicating that the serum effect is not dependent on synthesis of new protein. Incubation with palmitic acid caused a marked increase of phosphatidylinositol specific activity, little change in specific activity of phosphatidic acid but a tripling of its total amount, and no changes in the other phosphatides. Oleic acid caused only a small increase in phosphatidylinositol specific activity and no significant changes in the other lipids.

Thyrotropin stimulation of 32P incorporation into the phospholipids of canine thyroid adenocarcinoma

Six carcinomas of the canine thyroid were studied. Five of the six tumors were functional on 131I scan and caused hyperthyroidism in two cases. The tumors were all of predominantly compact cellular histology with rare to moderate numbers of microfollicles. After surgical removal tumor slices were incubated with 32P in Krebs-Ringer-tris buffer with or without 0.1 U/ml of bovine TSH, and the specific activity of the extracted phospholipids was measured. TSH stimulated phosphatide turnover clearly in 5 cases and probably also in the 6th. Analysis of fractionated phospholipids in 2 cases showed that the response to TSH was mainly in the phosphatidic acid and phosphatidylinositol. These studies show that a malignant tumor may still retain at least one complete control system extending from TSH receptors to the final metabolic response.

Uptake of 67Ga in the lactating breast and its persistence in milk: case report

The concentration of 67Ga in the milk of a postpartum woman was measured at intervals up to 8 days after the injection of 3 mCi of 67Ga-citrate. The 67Ga concentration was about 0.15 muCi/ml at 3 days after injection and fell to 0.035 muCi/ml by 8 days. Since the biologic clearance of gallium was slow (T1/2 approximately 9 days), the major determinant of the clearance of radioactivity was the physical decay of the gallium. An estimate of the radiation dose to a nursing infant suggests that nursing be interrupted for about 2 weeks after the mother has had a 67Ga study.

Activation of bovine liver glycerol kinase by ethanol

The crystallization of bovine glycerol kinase (ATP:glycerol 3-phosphotransferase EC 2.7.1.30) is reported along with a study on the unusual activation of this enzyme by ethanol. The enzyme was extracted from calf lever andusual activation of this enzyme by ethanol. The enzyme was extracted from calf liver and purified 5900-fold giving crystals with a 5% yield. The kinetics of the enzyme with regard to glycerol and ATP were studied by varying the concentration of one substrate while keeping the other at saturating levels, and the effect of ethanol was observed by adding it at levels of 5% (v/v). Ethanol increased the V in both cases almost 2-fold. The apparent Km of ATP was 3.5 - 10(-6) and was increased to 7.6 - 10(-6) in the presence of ethanol. The apparent Km for glycerol was 3 - 10(-5) and was increased to 12 - 10(-5) when ethanol was added. A number of other alcohols had a similar activating effect except for 1,2-diols which only inhibited the enzyme. These findings are consistent with the explanation that alcohols compete with glycerol (hence also with the glycerophosphate product) for a hydroxy binding site on the enzyme. This leads to more rapid dissociation of the glycerophosphate (i.e. an increase in the steady-state constant, "k+2" resulting in an increased V).