Prognostic information from cytogenetic analysis in chronic B-lymphocytic leukemia and leukemic immunocytoma

Fifty-five patients with a clonal expansion of B lymphocytes in the peripheral blood were studied. According to the Kiel classification, 22 patients had chronic lymphocytic leukemia (CLL), 29 had immunocytoma (IC), two had prolymphocytic leukemia, and one had centrocytic lymphoma; one was not subclassified. Cytogenetic studies after B cell mitogen stimulation showed that six patients had an extra chromosome 12 as the sole abnormality. Another ten patients had an extra chromosome 12 together with other abnormalities. One patient had dup(12). Fifteen patients showed clonal aberrations without +12. Eleven patients showed only normal metaphases, and 12 patients were not evaluated cytogenetically. The cytogenetic subgroup pattern did not distinguish between CLL and IC patients. There was no significant difference between the CLL and IC groups as regards clinical findings and prognosis. However, the cytogenetic typing proved to be of prognostic significance. Increasing numbers of chromosomal aberrations within the cell clone were significantly associated with a poorer prognosis, ie, with impairment of survival (P = .04) and therapy-free survival (P less than 10(-4]. Patients with complex karyotypes (at least clonal aberrations) showed the poorest survival (P = .007). Patients with +12 required treatment earlier than patients with a normal karyotype (P = .01) and patients with karyotypic changes other than +12 (P = .006). These latter differences were even more pronounced when only IC patients were considered (P = .005 and P = .002, respectively). A multivariate analysis revealed that +12 was as strong an indicator of poor survival as advanced Rai or Binet stages and a stronger predictor of therapy-demanding disease.     

Limited predictive value of an acute test with subcutaneous octreotide for long-term IGF-I normalization with Sandostatin LAR in acromegaly

OBJECTIVES: To study whether the growth hormone (GH) response after the subcutaneous administration 50 microg of octreotide (acute octreotide test) has any predictive value for long-term IGF-I normalization with Sandostatin LAR. DESIGN: Twenty four therapy-naive patients with active acromegaly were studied. RESULTS: > 75% GH decrease in the acute octreotide test predicted long-term IGF-I normalization with Sandostatin LAR in 8/11 (73%) of patients. 3/13 (23%) patients with < 75% GH decrease in the acute octreotide test were long-term biochemically controlled with Sandostatin LAR. Using the > 75% GH reduction criterion, the sensitivity and specificity of this test for predicting long-term normalization of serum IGF-I with Sandostatin LAR treatment were 73% and 77%, respectively (positive and negative predictive values: 73% and 77%, respectively). 6/8 (75%) patients with GH suppression to levels < 1.1 microg/l and 9/16 (56%) patients with GH suppression to levels < 2 microg/l in the acute octreotide test showed normalization of serum IGF-I with long-term Sandostatin LAR treatment. The sensitivity and specificity of GH suppression < 1.1 microg/l for predicting of the long-term normalization of serum IGF-I with Sandostatin LAR therapy were 55% and 85%, respectively (positive and negative predictive values: 75% and 69%, respectively). The sensitivity and specificity of GH suppression < 2 microg/l for predicting of the long-term normalization of serum IGF-I with Sandostatin LAR therapy were 82% and 46%, respectively (positive and negative predictive values: 56% and 75%, respectively). CONCLUSION: The acute octreotide is not recommended for clinical decision making with regard to long-term treatment using the long-acting somatostatin analog Sandostatin LAR in acromegaly.     

Experimentally induced prolonged magnesium deficiency causes osteoporosis in the rat

Background: It has been shown that prolonged daily peroral magnesium (Mg) administration, as tabs of Mg(OH)(2), used as the only treatment in postmenopausal osteoporosis, causes a significant increase in BMD. Objective: In order to obtain definitive evidence of causality of magnesium deficiency in the etiology of osteoporosis, we spent 1 year examining rats given a daily Mg-deficient diet (200 ppm) and compared them with rats given a Mg-adequate diet (2000 ppm). Methods: Sixteen female Sprague-Dawley rats, mean weight 110 (S.D. 23) g, were divided into two groups and randomly assigned to a semisynthetic diet that differed only in Mg content. Urine samples were collected every 3 months and blood was collected at the end of the trial. After the animals were sacrificed, the L3-L5 vertebrae and the femoral regions were examined for bone density (BMD) using dual energy X-ray absorptiometry. The femoral bones were examined for bone fragility and the tibiae by histomorphometry, and the mineral content of the bones was estimated. Results: The mean BMD of L3-L5 vertebral bone was significantly higher in group A (adequately nourished) than in the Mg-deficient group B (p=0.035, one-tail); in addition, the BMD of the femural region was significantly higher in group A (p=0.045, one-tail). The bending stiffness of the femur was slightly higher in group A than in group B; however, after correction to diminish the influence of the difference in bone dimensions between the two groups, femur rigidity (i.e., the loss of elasticity) in group B became significantly higher than that in group A (p=0.024). The force needed to break the bone was significantly higher in group A than in group B (p=0.024) and it remained higher after correction, although no longer significantly. In group B, the diminution of the trabecular bone volume, in relation to tissue volume (BV/TV), and the increase in the degree of trabecular interconnection (TBPf) clearly showed the presence of osteoporosis. On microscopy, focal osteoporosis of the metaphyseal spongious bone was observed in the bone rendered Mg-deficient. Conclusions: Because osteoporosis is characterized by lowering of BMD, increased bone fragility, and altered bone architecture, our study showed that maintaining rats for 1 year on a Mg-deficient diet gives rise to the appearance of osteoporosis.     

DRD2 Dopamine Receptor Genotype, Linkage Disequilibrium, and Alcoholism in American Indians and Other Populations

We defined interpopulation differences in the frequency of the dopamine D2 receptor DRD2/Taq1 A1 allele, which has previously been associated with alcoholism. Frequencies of the A1 allele in unrelated subjects were 0.18 to 0.20 (se = 0.02 to 0.03) in several Caucasian populations previously assessed, 0.38 (±0.05) in American Blacks ( n = 44), 0.63 (±0.07) in Jemez Pueblo Indians ( n = 23), and 0.80 (± 0.04) in Cheyenne Indians ( n = 52). The existence of large interpopulation differences in the frequency of the Taq1 alleles suggests that associations to disease status could readily be generated or masked if disease and control groups were uneven in ethnic composition. To address the possibility that the 4-fold higher frequency of the A1 allele in Cheyenne Indians was related to an increased vulnerability to alcoholism in that population, 47 Cheyenne Indians were psychiatrically interviewed and blind-rated. However, there was no significant difference between interviewed controls (0.73 ± 0.06, n = 24), subjects with alcoholism and/or drug abuse (0.74 ± 0.06, n = 23) and noninterviewed population controls (0.87 ± 0.05, n = 20). Legitimate association of the DRD2/Taq1 allele to alcoholism would presumably require it to be in linkage disequilibrium (nonrandom association) with a functional mutation at DRD2 or elsewhere. The level of disequilibrium would vary between populations and could place an upper bound on the strength of an association. To provide a model for the extent and variation of disequilibrium at DRD2, the level of linkage disequilibrium between the Taq1 RFLP and a second DRD2 polymorphism, the SSCP variant in the immediate 3'region of the gene, was determined in three populations. The normalized disequilibrium values were 0.36 In U.S. Caucasians ( n = 48), 0.34 in Finns ( n = 86), and 0.78 in Cheyenne Indians ( n = 34).     

ERCC1 mutations impede DNA damage repair and cause liver and kidney dysfunction in patients

ERCC1-XPF is a multifunctional endonuclease involved in nucleotide excision repair (NER), interstrand cross-link (ICL) repair, and DNA double-strand break (DSB) repair. Only two patients with bi-allelic ERCC1 mutations have been reported, both of whom had features of Cockayne syndrome and died in infancy. Here, we describe two siblings with bi-allelic ERCC1 mutations in their teenage years. Genomic sequencing identified a deletion and a missense variant (R156W) within ERCC1 that disrupts a salt bridge below the XPA-binding pocket. Patient-derived fibroblasts and knock-in epithelial cells carrying the R156W substitution show dramatically reduced protein levels of ERCC1 and XPF. Moreover, mutant ERCC1 weakly interacts with NER and ICL repair proteins, resulting in diminished recruitment to DNA damage. Consequently, patient cells show strongly reduced NER activity and increased chromosome breakage induced by DNA cross-linkers, while DSB repair was relatively normal. We report a new case of ERCC1 deficiency that severely affects NER and considerably impacts ICL repair, which together result in a unique phenotype combining short stature, photosensitivity, and progressive liver and kidney dysfunction.     

Fc-Fc interactions of human IgG4 require dissociation of heavy chains and are formed predominantly by the intra-chain hinge isomer

Human IgG4 antibodies are remarkable not only because they can dynamically exchange half-molecules (Fab-arm exchange) but also for their ability to interact with the Fc part of IgG4 and other IgG subclasses. This rheumatoid factor-like binding of IgG4 does not appear to take place spontaneously, because it is only observed to solid-phase or antigen-bound IgG. We hypothesized that Fc-Fc interactions might involve (partial) dissociation of heavy chains. We investigated the molecular basis of these Fc-Fc interactions, and found that the structural features important for the exchange reaction also control the Fc binding activity. In particular, if arginine-409 in the CH(3)-CH(3) interface in IgG4 is mutated to lysine (the equivalent in IgG1), Fc-Fc interactions are formed 3 orders of magnitude less efficiently compared to the wild-type. This mutation was previously found to increase the CH(3)-CH(3) interaction strength in IgG4. Furthermore, of the two hinge isomers of IgG4, the intra-chain (non-covalently linked) form was found to form Fc-Fc interactions, but not the inter-chain form. Together, these results demonstrate that Fc-Fc interactions of IgG4 involve (partial or complete) dissociation of heavy chains. The promiscuity to other IgG subclasses suggests that IgG4 might act as scavenger to IgG molecules with impaired structural integrity.     

Mental rotation strategies reflected in event‐related (de)synchronization of alpha and mu power

During a mental rotation task of hands, participants mentally rotate their hand into the orientation of the shown hand. These mental movements are subject to the body's biomechanical constraints. In this study, we investigated whether the involvement of motor processes during the mental rotation process, as reflected in mu‐power desynchronization, is also influenced by one's movement capabilities. We performed an EEG study and used a delayed response mental rotation task of hands to examine the event‐related desynchronization differences between movements that are biomechanically easy and difficult to perform. Our results show an increase in event‐related desynchronization of the mu power for biomechanically easy compared to difficult‐to‐adopt postures. These findings provide further evidence for the notion that motor simulations can only be performed for movements that can already be performed overtly.     

Development and Evaluation of an Affordable Real-Time Qualitative Assay for Determining HIV-1 Virological Failure in Plasma and Dried Blood Spots

Virological failure (VF) has been identified as the earliest, most predictive determinant of HIV-1 antiretroviral treatment (ART) failure. Due to the high cost and complexity of virological monitoring, VF assays are rarely performed in resource-limited settings (RLS). Rather, ART failure is determined by clinical monitoring and to a large extent immunological monitoring. This paper describes the development and evaluation of a low-cost, dried blood spot (DBS)-compatible qualitative assay to determine VF, in accordance with current WHO guideline recommendations for therapy switching in RLS. The assay described here is an internally controlled qualitative real-time PCR targeting the conserved long terminal repeat domain of HIV-1. This assay was applied to HIV-1 subtypes A to H and further evaluated on HIV-1 clinical plasma samples from South Africa (n = 191) and Tanzania (n = 42). Field evaluation was performed in Uganda using local clinical plasma samples (n = 176). Furthermore, assay performance was evaluated for DBS. This assay is able to identify VF for all major HIV-1 group M subtypes with equal specificity and has a lower detection limit of 1.00E+03 copies/ml for plasma samples and 5.00E+03 copies/ml for DBS. Comparative testing yielded accurate VF determination for therapy switching in 89% to 96% of samples compared to gold standards. The assay is robust and flexible, allowing for “open platform” applications and producing results comparable to those of commercial assays. Assay design enables application in laboratories that can accommodate real-time PCR equipment, allowing decentralization of testing to some extent. Compatibility with DBS extends access of sampling and thus access to this test to remote settings.