Deficient expression of MHC class II antigens in some cases of human B cell leukaemia

Cells from the peripheral blood of patients with B cell chronic lymphocytic leukaemia (B-CLL) and acute lymphoblastic leukaemia (ALL) were examined for the expression of MHC class II antigens, using a number of monoclonal antibodies (MoAb) including L243 (anti-DR) and TU22 (anti-DQ). There was wide variation in expression of MHC class II antigens in CLL, both from patient to patient and among cells from the same individual. In a number of subjects a significant proportion of the cells had detectable levels of expression of DR antigens but not of DQ antigens. In some cases of ALL although almost all cells were MHC class II positive, DQ expression was undetectable. Differentiation of CLL cells, induced by culturing the cells with 12-0-tetradecanoyl phorbol-13-acetate (TPA), was accompanied by increases in MHC class II expression at the cell surface of up to more than 20-fold, and resulted in detectable expression of DQ antigens on greater than 90% of the cells in all the subjects studied.     

Strategy for diagnosis of congenital toxoplasmosis: evaluation of methods comparing mothers and newborns and standard methods for postnatal detection of immunoglobulin G, M, and A antibodies

In a study involving 14 laboratories supported by the European Community Biomed 2 program, we evaluated immunologic methods for the postnatal diagnosis of congenital toxoplasmosis (CT). Among babies born to mothers who seroconverted to positivity for toxoplasmosis during pregnancy, we analyzed 55 babies with CT on the basis of persistent anti-Toxoplasma immunoglobulin G (IgG) at 1 year of life and 50 control babies without anti-Toxoplasma IgG at 1 year of life in the absence of curative treatment with pyrimethamine-sulfonamides. We tested in-house methods such as the enzyme-linked immunofiltration assay (ELIFA) or Immunoblotting (IB) for the detection of IgG or IgM; these methods allowed comparison of the immunologic profiles of the mothers and the infants. We compared ELIFA and IB with a commercial enzyme immunoassay (EIA) or in-house immunosorbent agglutination assay (ISAGA) for the detection of IgM or IgA. The performances of combinations of methods were also assessed. A cumulative sensitivity of 98% during a 1-year follow-up was obtained with the ELIFA plus ISAGA combination. Only one case of CT was missed by the ELIFA plus ISAGA combination, whereas three cases were missed by the IB plus ISAGA combination, even though 48% of patients with CT were treated with pyrimethamine-sulfonamides, which are known to inhibit antibody neosynthesis. A similar performance was obtained with either ELIFA or IB in combination with EIA. The difference in performance between ELIFA plus ISAGA and IB plus ISAGA was not statistically significant (P = 0.31), and we conclude that both combinations of tests can be used for the diagnosis of CT in newborns.     

Inv(X)(p21.1;q22.1) in a man with mental retardation,short stature,general muscle wasting,and facial dysmorphism: clinical study and mutation analysis of the NXF5 gene

We describe a 59-year-old male (patient A059) with moderate to severe mental retardation (MR) and a pericentric inversion of the X-chromosome: inv(X)(p21.1;q22.1). He had short stature, pectus excavatum, general muscle wasting, and facial dysmorphism. Until now, no other patients with similar clinical features have been described in the literature. Molecular analysis of both breakpoints led to the identification of a novel "Nuclear RNA export factor" (NXF) gene cluster on Xq22.1. Within this cluster, the NXF5 gene was interrupted with subsequent loss of gene expression. Hence, mutation analysis of the NXF5 and its neighboring homologue, the NXF2 gene was performed in 45 men with various forms of syndromic X-linked MR (XLMR) and in 70 patients with nonspecific XLMR. In the NXF5 gene four nucleotide changes: one intronic, two silent, and one missense (K23E), were identified. In the NXF2 gene two changes (one intronic and one silent) were found. Although none of these changes were causative mutations, we propose that NXF5 is a good candidate gene for this syndromic form of XLMR, given the suspected role of NXF proteins is within mRNA export/transport in neurons. Therefore, mutation screening of the NXF gene family in phenotypically identical patients is recommended.     

Complete Primary Sequences of Two λ Immunoglobulin Light Chains in Myelomas with Nonamyloid (Randall-Type) Light Chain Deposition Disease

We herein report on the first two primary sequences (BOU and RAC) of monoclonal light chains of the λ type responsible for nonamyloid λ light chain deposition disease. Both patients were affected with severe forms of myeloma complicated with renal failure. The pathological presentation typically featured Congo red-negative deposits along tubular basement membranes but differed somewhat from the typical “Randall-type” κ light chain deposition disease: they lacked the prominent glomerulosclerosis pattern often featuring nonamyloid κ deposits and were associated with cylinders or myeloma casts. Both protein sequences were deduced from those of the corresponding complementary DNAs in the bone marrow plasma cells. For each chain, products of three independent amplifications by polymerase chain reaction were sequenced and found to be identical. BOU and RAC λ mRNAs had a normal overall structure consisting of Vλ2 segments rearranged to Jλ2Cλ2 but displayed a number of unusual features within their primary sequences. These substitutions are likely responsible for changes in light chain conformation that promote their aggregation and deposition along renal tubule basement membranes.     

The volume-activated chloride current in human endothelial cells depends on intracellular ATP

We have studied the effect of intracellular ATP on volume-activated Cl^–-currents in endothelial cells from human umbilical veins by means of the whole-cell patch clamp technique. The run-down of this current in ruptured patches during repetitive applications of hypotonic solutions (HTS) could be significantly reduced if the cells were internally perfused with a pipette solution that contained 4 mmol/l ATP. This run-down was much less pronounced if currents were recorded using nystatin-perforated patches. The amplitude of the current was drastically reduced and its activation became slower if the cells were superfused with a glucose-free medium with 1 mmol/l KCN. Adding 4 mmol/l ATPS, a poorly hydrolyzable ATP-analogue, to the patch pipette prevented run-down of the current during repetitive activations by HTS, even if the cells were superfused with glucose-free solution with 1 mmol/l KCN. It is concluded that activation of the mechanosensitive Cl^– conductance in human endothelial cells requires the presence of intracellular ATP, but not its hydrolysis.     

Bilateral salpingectomy does not compromise ovarian stimulation in an in-vitro fertilization/embryo transfer programme

The question whether salpingectomy has a negative influenceon ovarian function and the outcome of pregnancy in an in-vitrofertilization (IVF) and embryo transfer treatment programmeis not yet answered. We performed a retrospective case-controlstudy to investigate the possible negative effect of salpingectomyon ovarian response to human menopausal gonadotrophins (HMG)during IVF and embryo transfer. The study group was composedof 26 patients with bilateral salpingectomy. In 67 cycles weanalysed different parameters of ovulation such as the numberof days of ovarian stimulation, numbers of ampoules of HMG,pre-ovulatory oestradiol concentrations and the numbers of oocytesretrieved. These parameters were compared to a control groupof 134 cycles in 134 women with healthy Fallopian tubes. Nodifferences were found. Implantation ratio, pregnancy rate andoutcome were the same in both groups. We conclude that bilateralsalpingectomy had no detrimental effect on ovarian performanceduring IVF and embryo transfer treatment nor on the outcome.     

Evidence for Classically Conditioned Fatigue Responses in Patients Receiving Chemotherapy Treatment for Breast Cancer

Fatigue is the most common side effect of chemotherapy for cancer. Not yet explored is the possibility that patients may develop conditioned fatigue responses to clinic cues as a result of the repeated pairing of the clinic environment (conditioned stimulus) with infusions of chemotherapy (unconditioned stimulus) that cause fatigue (unconditioned response). As a first critical test of this possibility, breast cancer patients (N = 82) were studied across their first four cycles of chemotherapy. Consistent with conditioning: (1) fatigue levels in the clinic environment significantly increased with repeated pairings of the clinic environment and chemotherapy administration; (2) fatigue responses in the clinic environment prior to the fourth infusion (CR) were predicted by patients’ previous experiences of post-infusion fatigue (UR) above and beyond effects of concurrent emotional distress. These results provide the first evidence in the literature that fatigue can be conditioned. Additional research is warranted to determine the clinical importance of this source of fatigue in chemotherapy patients.     

Morphofunctional ontogeny of the urinary system of the European sea bass Dicentrarchus labrax

European sea bass (Dicentrarchus labrax) are euryhaline fish that tolerate wide salinity fluctuations owing to several morphofunctional adaptations. Among the osmoregulatory sites (tegument, branchial chambers, digestive tract, urinary system), little is known about the kidney and the urinary bladder. The present study describes the ontogeny of the urinary system (kidney and urinary bladder) and focuses on the progressive expression of the Na⁺/K⁺-ATPase in the cells of these ion-transporting epithelia. A structural approach has shown that two pronephric urinary tubules are already present at hatching while the urinary bladder starts to differentiate. The glomus, an ultrafiltration site, occurs at day 5 (D5). The opisthonephros differentiates at D19/25 from the pronephric collecting tubules, then it rapidly grows longer and becomes folded. Na⁺/K⁺-ATPase immunolocalization and transmission electron microscopy show that ionocyte-like cells line the urinary tubules and the dorsal wall of the urinary bladder from D2/D5 on. Tubule ionocytes present a basolateral-localized fluorescence. Ionocytes of the collecting ducts and of the dorsal wall of the bladder present a fluorescence distributed in the whole cytoplasm. Fluorescence becomes stronger in later stages, suggesting a progressively increasing functionality of the urinary system in active ion transports. This observation is closely correlated with the ontogeny of osmoregulatory abilities. In juvenile and preadult fish kept in seawater, osmolality measurements demonstrate that urine is isotonic to blood. At low salinity, urine is hypotonic to blood in both stages. The capacity to produce hypotonic urine increases during ontogeny, a fact that suggests an increasing involvement of the urinary system in osmoregulation. The occurrence and the progressive functionality of the urinary system during the ontogeny, along with those of other osmoregulatory sites, are major adaptations allowing the sea bass to live in habitats of variable salinity such as lagoons and estuaries.     

A mutational hot spot in the KCNQ4 gene responsible for autosomal dominant hearing impairment

Several different mutations in the KCNQ4 K+ channel gene are responsible for autosomal dominant nonsyndromic hearing impairment (DFNA2). Here we describe two additional families originating from Europe and Japan with a KCNQ4 missense mutation (W276S) that was previously found in one European family. We compared the disease-associated haplotype of the three W276S-bearing families using closely linked microsatellite markers and intragenic single nucleotide polymorphisms. Differences between the haplotypes were found, excluding a single founder mutation for the families. Therefore, the W276S mutation has occurred three times independently, and most likely represents a hot spot for mutation in the KCNQ4 gene.