A case of spinal cord infarction caused by polycythemia vera

STUDY DESIGN

This is a case report.

OBJECTIVE

The objective of this study was to report on a 66-year-old woman with a confirmed diagnosis of polycythemia vera who presented with acute spinal cord infarction.

SETTING

A 66-year-old woman was previously diagnosed with polycythemia vera and presented with acute paraparesis and urinary retention.

RESULTS

The patient's platelet count was 847,000 platelets per μl. T2- and diffusion-weighted magnetic resonance imaging revealed hyperintensity at the T12-L1 spinal cord. Computed tomography of the abdominal aorta further revealed multiple thrombi filling the aortic lumen.

CONCLUSIONS

Polycythemia vera creates a high risk of systemic thrombosis due to hyperviscosity and platelet activation. Although acute infarction in the spinal cord is a rare complication of this myeloproliferative disease, it should be considered in all affected patients.

Utility of proton MR spectroscopy for differentiating typical and atypical primary central nervous system lymphomas from tumefactive demyelinating lesions

BACKGROUND AND PURPOSE

It may be challenging to differentiate primary CNS lymphomas, especially primary CNS lymphomas with atypical MR features, from tumefactive demyelinating lesions by the use of conventional MR. This study aimed to investigate the usefulness of (1)H-MR spectroscopy for making this discrimination.

MATERIALS AND METHODS

Forty-four patients with primary CNS lymphomas and 21 with tumefactive demyelinating lesions were enrolled. Single-voxel (TE = 144 ms) (1)H-MR spectroscopy scans with the use of the point-resolved spectroscopy sequence were retrospectively analyzed. The Cho/Cr and Cho/NAA area ratios were calculated. The lipid and/or lactate peak was visually categorized into 5 grades on the basis of comparison with the height of the Cr peak. The (1)H-MR spectroscopy findings were compared in all of the primary CNS lymphomas and the tumefactive demyelinating lesions and in the subgroup of atypical primary CNS lymphomas and tumefactive demyelinating lesions. The thresholds and added value of (1)H-MR spectroscopy to conventional MR were calculated by use of receiver operating characteristic curves.

RESULTS

Discrepancies between all of the primary CNS lymphomas and tumefactive demyelinating lesions were found in the Cho/Cr ratio (P = .000), Cho/NAA ratio (P = .000), and the lipid and/or lactate peak grade (P = .000). Lymphoma rather than tumefactive demyelinating lesions was suggested when the Cho/Cr ratio was >2.58, the Cho/NAA ratio was >1.73, and a high lipid and/or lactate peak grade (grade >3) was seen. Higher Cho/Cr ratios, Cho/NAA ratios, and lipid and/or lactate peak grades were found in atypical primary CNS lymphomas when compared with those of tumefactive demyelinating lesions. The area under the receiver operating characteristic curve of conventional MR was improved from 0.827 to 0.870 when Cho/NAA ratio was added in the uncertain cases.

CONCLUSIONS

(1)H-MR spectroscopy may be useful for differentiating primary CNS lymphomas from tumefactive demyelinating lesions. Cho/NAA ratio could provide added value to conventional MR imaging.

Proteomic analysis of the molecular response of Raji cells to maslinic acid treatment

Maslinic acid, a natural pentacyclic triterpene has been shown to inhibit growth and induce apoptosis in some tumour cell lines. We studied the molecular response of Raji cells towards maslinic acid treatment. A proteomics approach was employed to identify the target proteins. Seventeen differentially expressed proteins including those involved in DNA replication, microtubule filament assembly, nucleo-cytoplasmic trafficking, cell signaling, energy metabolism and cytoskeletal organization were identified by MALDI TOF-TOF MS. The down-regulation of stathmin, Ran GTPase activating protein-1 (RanBP1), and microtubule associated protein RP/EB family member 1 (EB1) were confirmed by Western blotting. The study of the effect of maslinic acid on Raji cell cycle regulation showed that it induced a G1 cell cycle arrest. The differential proteomic changes in maslinic acid-treated Raji cells demonstrated that it also inhibited expression of dUTPase and stathmin which are known to induce early S and G2 cell cycle arrests. The mechanism of maslinic acid-induced cell cycle arrest may be mediated by inhibiting cyclin D1 expression and enhancing the levels of cell cycle-dependent kinase (CDK) inhibitor p21 protein. Maslinic acid suppressed nuclear factor-kappa B (NF-κB) activity which is known to stimulate expression of anti-apoptotic and cell cycle regulatory gene products. These results suggest that maslinic acid affects multiple signaling molecules and inhibits fundamental pathways regulating cell growth and survival in Raji cells.

Ultra-slow oscillations in cortical networks in vitro

An ultra-slow oscillation (<0.01 Hz) in the network-wide activity of dissociated cortical networks is described in this article. This slow rhythm is characterized by the recurrence of clusters of large synchronized bursts of activity lasting approximately 1-3 min, separated by an almost equivalent interval of relatively smaller bursts. Such rhythmic activity was detected in cultures starting from the fourth week in vitro. Our analysis revealed that the propagation motifs of constituent bursts were strongly conserved across multiple oscillation cycles, and these motifs were more consistent at the electrode level compared with the neuronal level.

SBE-TAGS: an array-based method for efficient single-nucleotide polymorphism genotyping

Generating human single-nucleotide polymorphisms (SNPs) is no longer a rate-limiting step for genetic studies of disease. The number of SNPs in public databases already exceeds 200,000, and the total is expected to exceed 1,000,000 within a year. Rather, progress is limited by the inability to genotype large numbers of SNPs. Current genotyping methods are suitable for studying individual loci or at most a handful at a time. Here, we describe a method for parallel genotyping of SNPs, called single base extension-tag array on glass slides, SBE-TAGS. The principle is as follows. SNPs are genotyped by single base extension (SBE), using bifunctional primers carrying a unique sequence tag in addition to a locus-specific sequence. Because each locus has a distinct tag, the genotyping reactions can be performed in a highly multiplexed fashion, and the resulting product can then be "demultiplexed" by hybridization to the reverse complements of the sequence tags arrayed on a glass slide. SBE-TAGS is simple and inexpensive because of the high degree of multiplexing and the use of an easily generated, generic tag array. The method is also highly accurate: we genotyped over 100 SNPs, obtaining over 5, 000 genotypes, with approximately 99% accuracy.

BCR/ABL inhibition by an escort/phosphatase fusion protein

Cellular transformation by the BCR/ABL oncogene depends on the ABL-encoded tyrosine kinase activity. To block BCR/ABL function, we created a unique tyrosine phosphatase by fusing the catalytic domain of SHP1 (SHP1c) to the ABL binding domain (ABD) of RIN1, an established binding partner and substrate for c-ABL and BCR/ABL. This fusion construct (ABD/SHP1c) binds to BCR/ABL in cells and functions as an active phosphatase. ABD/SHP1c effectively suppressed BCR/ABL function as judged by reductions in transformation of fibroblast cells, growth factor independence of hematopoietic cell lines, and proliferation of primary bone marrow cells. In addition, the leukemogenic properties of BCR/ABL in a murine model system were blocked by coexpression of ABD/SHP1c. Both the "escort" function provided by ABD and the inhibitor function provided by the phosphatase of SHP1c were necessary for effective BCR/ABL interference. Expression of ABD/SHP1c also reversed the transformed phenotype of K562, a human leukemia-derived cell line. These results have direct implications for leukemia therapeutics and suggest an approach to block aberrant signal transduction in other pathologies through the use of appropriately designed escort/inhibitors.

Genetic analysis of rolled, which encodes a Drosophila mitogen-activated protein kinase

Genetic and molecular characterization of the dominant suppressors of D-raf(C110) on the second chromosome identified two gain-of-function alleles of rolled (rl), which encodes a mitogen-activated protein (MAP) kinase in Drosophila. One of the alleles, rl(Su23), was found to bear the same molecular lesion as rl(Sem), which has been reported to be dominant female sterile. However, rl(Su23) and the current stock of rl(Sem) showed only a weak dominant female sterility. Detailed analyses of the rl mutations demonstrated moderate dominant activities of these alleles in the Torso (Tor) signaling pathway, which explains the weak dominant female sterility observed in this study. The dominant rl mutations failed to suppress the terminal class maternal-effect mutations, suggesting that activation of Rl is essential, but not sufficient, for Tor signaling. Involvement of rl in cell proliferation was also demonstrated by clonal analysis. Branching and integration of signals in the MAP kinase cascade is discussed.

Dominant mutations of Drosophila MAP kinase kinase and their activities in Drosophila and yeast MAP kinase cascades

Eight alleles of Dsor1 encoding a Drosophila homologue of mitogen-activated protein (MAP) kinase kinase were obtained as dominant suppressors of the MAP kinase kinase kinase D raf. These Dsor1 alleles themselves showed no obvious phenotypic consequences nor any effect on the viability of the flies, although they were highly sensitive to upstream signals and strongly interacted with gain-of-function mutations of upstream factors. They suppressed mutations for receptor tyrosine kinases (RTKs); torso (tor), sevenless (sev) and to a lesser extent Drosophila EGF receptor (DER). Furthermore, the Dsor1 alleles showed no significant interaction with gain-of-function mutations of DER. The observed difference in activity of the Dsor1 alleles among the RTK pathways suggests Dsor1 is one of the components of the pathway that regulates signal specificity. Expression of Dsor1 in budding yeast demonstrated that Dsor1 can activate yeast MAP kinase homologues if a proper activator of Dsor1 is coexpressed. Nucleotide sequencing of the Dsor1 mutant genes revealed that most of the mutations are associated with amino acid changes at highly conserved residues in the kinase domain. The results suggest that they function as suppressors due to increased reactivity to upstream factors.

Uncovering the cultural context for quality of family caregiving for elders

This article is part of a symposium exploring issues in developing cross-culturally equivalent conceptualizations and measures for a study of elder family caregiving. This article describes the development of an instrument to measure quality of elder family caregiving among Anglo and Mexican American caregivers. Following a review of typical approaches for evaluating quality of caregiving, a cross-cultural standard for excellence in elder caregiving is described. An instrument consistent with the United Nations Universal Declaration of Human Rights, the QUALCARE Scale, is identified as an appropriate cross-cultural instrument for assessing the quality of elder family caregiving. Refinement of the QUALCARE Scale using Berry's model for cross-cultural research, which necessitated identification of appropriate cross-cultural indicators of quality, is described. Examples of this process of indicator clarification are given for several basic human rights, based on the cross-cultural research team members' experiences with Anglo and Mexican American caregivers.

Toward a cross-cultural perspective of family caregiving

This article is part of a symposium that explores the issues involved in developing cross-culturally equivalent conceptualizations and measures for studying family caregiving. The examples used are from the instrument development phase of an ongoing program of research designed to generate and test a theory that explains the quality of family caregiving for frail elders at home. This article provides the background for the symposium by introducing the symposium's unifying theme: cross-cultural equivalence. The process described is based on the experiences of the cross-cultural research team and Berry's model for developing cross-culturally equivalent research.

Toward a cross-cultural understanding of family caregiving burden

This article is part of a symposium describing the development of cross-culturally relevant instruments to measure familism, caregiver burden, and quality of elder caregiving among Anglo- and Mexican American caregivers. This article explores issues involved in measuring caregiving burden. Caregiving burden is thought to adversely affect family caregiving, but the influence of culture on perceptions of burden has not been explored. Because no research focuses on caregiving burden among Mexican American caregivers, the first step involved reviewing the literature for cultural factors influencing caregiving and using the expertise of the cross-cultural team to identify and compare the meaning of caregiving burden in both groups. Next, two instrumentation studies were done to analyze the items on Poulshock and Deimling's Burden Instrument for comparable meaning and internal consistency within and between groups. The third step involved assessing the validity of Poulshock and Deimling's conceptualization of burden cross-culturally.

The relevance of familism in cross-cultural studies of family caregiving

Although familism has been studied in both Mexican American and Anglo families, there is controversy about whether familism in both groups is the same. Research has shown great within-group variability, and in addition, the kinship structure in the two groups is fundamentally different. This article explores the cross-cultural issues in conceptualizing familism and its relevance to caregiving among Anglo and Mexican American caregivers. Based on data obtained in an ongoing research program, the process of arriving at similarities and differences in the expression of familism is discussed using Berry's criteria for achieving cultural equivalence.

Isolation and characterization of pectin methylesterase from papaya

Pectin methylesterase (PME) (EC 3.1.1.11) has been purified to apparent homogeneity from ripe papaya fruits. The purification protocol consisted of ammonium sulphate precipitation (60-80%) and cation exchange chromatography in CM Sepharose CL-6B and Mono S. Papaya PME consists of two components (PME 1 and PME 2), which have been shown to be isoenzymes by Ferguson plot analysis. The molecular weight of the enzyme is 27,000 while its isoelectric point is greater than pH 9.0. The N-terminal sequences of PME 1 and PME 2 are SVVTPNAVVADDGVFXFKTG. Both PME 1 and PME 2 showed optimum activities at pH 8.0 and 35 degrees C. The average Kms of PME 1 and PME 2 are 0.0071 and 0.0166 g/liter pectin respectively, while the corresponding average Vmaxs are 741 and 800 mumol methanol/min/mg protein, respectively. Papaya pectin methylesterase is activated by cations, but the effect is more pronounced for divalent than monovalent cations. Inhibition studies showed that sucrose is a noncompetitive inhibitor while p-chloromercuribenzoic acid has no significant effect on its activity.

A protein kinase similar to MAP kinase activator acts downstream of the raf kinase in Drosophila

D-raf, a Drosophila homolog of Raf-1, plays key roles in multiple signal transduction pathways. Dsor1, a putative factor downstream of D-raf, was genetically identified by screening of dominant suppressors of D-raf. Dsor1Su1 mapped on X chromosome significantly suppressed the D-raf mutant phenotypes, and the loss-of-function mutations of Dsor1 showed phenotypes similar to those of the D-raf null mutations. Dsor1Su1 also significantly suppressed the mutations of other terminal class genes acting further upstream of D-raf. Molecular cloning of Dsor1 revealed its product with striking similarity to the microtubule-associated protein (MAP) kinase activator and yeast PBS2, STE7, and byr1. Our genetic results demonstrate the connection between raf and the highly conserved protein kinase cascade involving MAP kinase in vivo.