The diagnostic value of thrombopoietin level measurements in thrombocytopenia

It has been reported that blood trombopoietin (TPO) levels can discriminate between thrombocytopenia due to increased platelet destruction and decreased platelet production. With our TPO ELISA and a glycocalicin ELISA we analysed a large group of patients in detail and could confirm and amplify the above notion in detail. TPO levels were determined in plasma from 178 clinically and serologically well-defined thrombocytopenic patients: 72 patients with idiopathic autoimmune thrombocytopenia (AITP), 29 patients with secondary AITP, 5 patients with amegakaryocytic thrombocytopenia and 72 patients who suffered from various diseases (46 in whom megakaryocyte deficiency was not and 26 in whom it was expected). In addition, we measured the level of glycocalicin as a marker of total body mass of platelets. In all patients with primary AITP and secondary AITP, TPO levels were within the normal range or in some (n = 7) cases only slightly increased. The level of glycocalicin was not significantly different from that of the controls (n = 95). The patients with amegakaryocytic thrombocytopenia had strongly elevated TPO levels and significantly decreased glycocalicin levels. Similarly, among the 72 thrombocytopenic patients with various disorders, elevated TPO levels were only found in patients in whom platelet production was depressed. The mean level of glycocalicin in these patients was decreased compared to that in controls and patients with AITP, but was not as low as in patients with amegakaryocytic thrombocytopenia. In conclusion, all patients with depressed platelet production had elevated levels of circulating TPO, whereas the TPO levels in patients with an immune-mediated thrombocytopenia were mostly within the normal range. Therefore, measurement of plasma TPO levels provides valuable diagnostic information for the analysis of thrombocytopenia in general. Moreover, treatment with TPO may be an option in AITP.     

Hemolytic properties and riboflavin synthesis of Helicobacter pylori: cloning and functional characterization of the ribA gene encoding GTP-cyclohydrolase II that confers hemolytic activity to Escherichia coli

Various strains of Helicobacter pylori were able to lyse erythrocytes from sheep, horse, and human when grown on blood agar. The hemolysis did not depend on the production of the vacuolating cytotoxin VacA as demonstrated by the hemolytic behavior of an isogenic vacA-negative mutant strain. The hemolytic activity could be detected in cell-free supernatants and was not regulated by iron. To isolate genes coding for proteins involved in the destruction of erythrocytes, a plasmid-based DNA library was screened for expression of lytic activity on blood agar. This approach revealed that the H. pylori ribA gene confers hemolytic properties to Escherichia coli. The ribA gene encodes the enzyme GTP-cyclohydrolase II [EC 3.5.4.25] that catalyzes the initial step in the synthesis of riboflavin. The predicted amino acid sequence of the H. pylori RibA protein showed a high degree of similarity to equivalent enzymes from microorganisms and from plants. The single gene on a plasmid restored riboflavin synthesis in a ribA mutant of E. coli and induced hemolytic activity. Furthermore, ribA overexpression was associated with the production of a fluorescent yellow molecule that was not identical with riboflavin. Hemolysis was also seen for the ribA gene from E. coli, indicating that this feature was not specific for the H. pylori gene. The presence of ribA in various H. pylori strains was confirmed by Southern blot hybridization and by polymerase chain reaction with specific primers. This analysis revealed that microdiversity exists within the DNA region upstream from ribA, which was further confirmed by nucleotide sequence analysis.     

Kinetic study on the alkaline degradation of cotton hydrocellulose

The kinetics of alkaline degradation of cotton hydrocellulose were determined in 5% NaOH at various temperatures. An activation energy of 24 kcal./mole was found for the endwise degradation reaction, while that of termination to a stable m-saccharinic acid endunit is 32 kcal./mole. Consequently, the DP_n of the degradable chain length is highly dependent on the reaction temperature, being 1000 at 65°C. and 140 at 132°C. At lower temperatures, the majority of degrading chains terminate to a normal reducing endgroup at the crystalline–amorphous transition region. From the data, the D P_n of cellulose chain segments participating in the amorphous regions of the original cotton fibril was calculated to be 143. This result strongly supports the classical micellar fibril structure over the folded model proposed by Manley.     

Lymphography in testicular tumors (author's transl)

Results of lymphography in 101 cases of testicular tumor are described. Secondaries could be shown in 43% of seminomas and 46% of teratomas. Examples show the criteria of lymphographic diagnosis of secondaries. Lymphography permits a) more exact classification of stages b) better planning and control of treatment and c) prognosis.     

Silicon doping by nuclear transmutation

This paper describes, from the view of nuclear physics and radiochemistry, the mode of operation in doping semiconductor silicon with phosphorus by neutron irradiation. In addition to precise control of the irradiation fluence, this includes control of neutron-flux distribution, self-shielding and radioactive products from the silicon matrix and the surface impurities. The accuracy of the resistivity values achieved by this method is better than ± 5% at the predicated value. The good homogeneity of the dopant distribution is shown by the results of location-resolving resistivity measurements as well as by the breakdown radiation emitted by diodes. Neutron-bombarded homogeneously doped silicon (NBH-silicon) is used for routine manufacture of multi-diode vidicons and power devices.     

Neural networks provide superior description of Giardia lamblia inactivation by free chlorine

Use of conventional models to describe data on microbial inactivation during disinfection suffers from limitations with respect to flexibility and direct quantitative incorporation of water quality variables. This paper develops an approach to analysis of such data using neural networks (NNs). Using the data on free chlorine inactivation of Giardia lamblia previously reported, it was found that the use of an NN with a single hidden layer and four hidden neurons provided a superior (better) fit to the data with a reduced number of model parameters when compared to the fitting of this data using a conventional approach. Therefore, the use of NN models should be considered in the future assessment of microbial inactivation during disinfection. Incorporation of additional facets of the disinfection process, such a disinfectant decay, needs to be considered in subsequent development of this approach.     

Bupropion in breast milk: an exposure assessment for potential treatment to prevent post-partum tobacco use

Objectives: To assess potential infant exposure to bupropion and its active metabolites in breast milk such as would occur during treatment to prevent post-partum relapse to tobacco use, and to compare the concentrations of bupropion in urine and saliva with plasma and breast milk.

Design and setting: Cohort study, outpatient clinical research centre.

Subjects: Ten healthy post-partum volunteers who agreed to take bupropion for seven days, pump and discard their breast milk, and have samples of breast milk, plasma, saliva, and urine analysed.

Intervention: Bupropion 150 mg a day for three days and then 300 mg a day for four days.

Main outcome measures: Concentrations of bupropion and its active metabolites (hydroxybupropion, erythrohydrobupropion, threohydrobupropion) in breast milk, plasma, saliva, and urine. Determination of average infant exposure.

Results: The calculated average dosage of bupropion in breast milk was 6.75 µg/kg/day. Therefore, the average infant exposure is 0.14 % of the standard adult dose of bupropion, corrected for the difference in body weight. Considering the sum of bupropion and its active metabolites, the average infant exposure is expected to be 2% of the standard maternal dose on a molar basis. The concentration of bupropion and its active metabolites in breast milk was not associated with age, body mass index, use of oral contraceptive pills, age of infant, or the frequency of breast feeding at the time the study was initiated. The coefficient of determination (r²) between the concentration of bupropion in breast milk and in urine was 0.77 (p < 0.01).

Conclusions: Bupropion and its active metabolites are present in the breast milk of lactating women. The concentrations of bupropion in breast milk and urine were highly correlated. These results indicate that the daily dose of bupropion and metabolites that would be delivered to an infant of a woman taking a therapeutic dose of bupropion is small. These results suggest that the effectiveness of bupropion to prevent post-partum relapse to tobacco use should be evaluated without excluding women who plan to breast feed.

     

A new removable resist for high aspect ratio applications

A variety of different photo resists are used for fabrication of MEMS. Presently good results were reported for SU-8, a chemically amplified negative tone photoresist. But SU-8 has a disadvantage for some applications in LIGA technique, especially in the X-ray mask fabrication. After processing the finished resist pattern are hardly soluble from the substrate. This paper will briefly describe the current status of the development of the new negative tone photoresist CAR 44 whose big advantage is the easy removableness of the cross linked pattern. This work widely uses the contents of the presentation “A New Removable Resist for High Aspect Ratio Applications” to the High Aspect Ratio Micro Structure Technology workshop HARMST 2005 held in Gyeongyu (Republic of Korea), June 10–13, 2005.     

Teachers' stereotypes of Asian, Black, and White students.

This research uses two different measurement operations to examine contemporary stereotypes of Asians, Blacks, and Whites held by an ethnically diverse sample of teachers. Data were drawn from a sample of 188 teachers representing over 160 schools in Southern California. Consistent with previous research, participants endorsed a "model minority" stereotype of Asians with regard to intelligence, academic striving, introversion, and rule compliance. Contrary to expectation, there was substantial congruence in the degree of uniformity and favorableness of the stereotypic traits associated with Blacks and Whites, with participants' revealing both strong positive and negative trait associations. The use of both open-ended and fixed-format measurement strategies revealed some method variation in the assessment of participants racial beliefs, with the open-ended format suggesting more complex and heterogeneous racial representations. Results are discussed in terms of methodological issues in stereotype assessment and implications for reducing the impact of racial biases in psychoeducational evaluations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)