Spondylometaphyseal dysplasia, corner fracture type: a heritable condition associated with coxa vara

The authors present the radiographic features of a previously incompletely delineated bone dysplasia, which they call spondylometaphyseal dysplasia, corner fracture type. This is a dominant heritable condition associated with short stature and developmental coxa vara. The progressive hip deformity usually causes significant disability requiring surgical correction. Developmental coxa vara, simulated corner fractures of long tubular bones, and vertebral body abnormalities result in a diagnostic constellation. Knowledge of these distinctive radiologic features allows accurate diagnosis, which in turn should lead to appropriate genetic counseling and possibly to earlier, more efficacious surgical treatment of the coxa vara.     

Essential thiol and disulphide groups in the histamine H1-receptor signal transfer of guinea-pig parenchymal lung strips

Guinea-pig parenchymal lung strips contract after H₁-receptor stimulation and membrane depolarisation with KCl. Contractions after 50 mM KCl were similar to the maximal histamine response. Treatment of lung strips with micromolar concentrations of the thiol-alkylator N-ethylmaleimide markedly affects both histamine H₁-receptor mediated and 50 mM KCl-induced contractions. The H₁-receptor response was only affected via a decrease in the maximal response. The response to 50 mM KCl was also inhibited after thiol-alkylation. However, H₁-receptor responses appeared to be slightly more sensitive towards thiol-alkylation compared to KCl-responses. Reduction of disulphide groups with 1,4-dithiothreitol also modified the contractile responses to both stimuli. It is concluded that both thiol- and disulphide moieties play important roles in the regulation of histamine H₁-receptor activity.     

Requirements for the internalization of a murine monoclonal antibody directed against the HER-2/neu gene product c-erbB-2.

A murine monoclonal antibody, TA1, is directed against an epitope on the extracellular domain of the HER-2/neu (c-erbB-2) gene product. Requirements for TA1-induced internalization of c-erbB-2 have been studied using the SKBr3 human breast cancer cell line and several rat fibroblast cell lines that express either wild-type or mutant human c-erbB-2. Internalization of TA1 was monitored by assaying protease-resistant uptake of 125I-labeled TA1, by electron microscopy of gold-labeled TA1, and by inhibition of clonogenic growth of cells incubated with TA1 that had been conjugated with blocked ricin. Similar rates of internalization of TA1 were observed in SKBr3 and in rat fibroblasts that expressed human c-erbB-2. The route of endocytosis was the same as that observed with antibodies against other membrane receptors. Anti-c-erbB-2 and anti-transferrin receptor cointernalized through clathrin-coated pits, coated vesicles, endosomes, and multivesicular bodies. Products of mutant c-erbB-2 that lacked a portion of the tyrosine kinase domain or that lacked most of the cytoplasmic domain were endocytosed in the presence of TA1 as promptly as the wild-type c-erbB-2 product. Slightly more rapid internalization of TA1 was observed in rat cells that expressed c-erbB-2 with a single point mutation in the transmembrane domain. Taken together, our data suggest that neither the intracytoplasmic domain nor receptor phosphorylation is required for antibody-mediated endocytosis of c-erbB-2.     

Clinical significance of hematologic parameters in non-Hodgkin's lymphoma at diagnosis

Three hundred seventeen patients with non-Hodgkin's lymphoma (NHL) (54 low grade, 180 intermediate grade, 76 high grade, and seven unclassified) treated with chemotherapy were evaluated for the presence of hematologic abnormalities at diagnostic staging. Anemia was present in 42%, leukopenia in 6%, thrombocytopenia in 13%, leukocytosis in 26%, and thrombocytosis in 14% at presentation. The presence of bone marrow involvement by lymphoma was more likely to be associated with leukopenia and thrombocytopenia than the absence of bone marrow involvement. Although anemia was slightly more common in patients with bone marrow lymphoma than in those without marrow lymphoma, the difference was not statistically significant. Hematologic parameters were similar for patients with B-cell or T-cell lymphoma. Evidence of bone marrow failure with multiple cytopenias was present in 26 patients (8%). Leukoerythroblastosis was present in 2%. Circulating lymphoma was present in 9.5%. Anemic patients had a shorter survival time than nonanemic patients, whether bone marrow was involved by lymphoma or not. Survival was not affected by the presence of leukopenia or mild leukocytosis, but, in patients without marrow lymphoma, leukocytosis with a leukocyte count greater than 20 x 10(9)/l was associated with short survival length. Thrombocytopenia was associated with short survival time only in patients with bone marrow involvement by lymphoma. Patients with multiple cytopenias or leukoerythroblastosis had short survival times, but the presence of circulating lymphoma did not alter survival when compared with other patients with bone marrow involvement by lymphoma. These data suggest that hematologic evaluation at the time of diagnostic staging of NHL provides useful prognostic information that may have therapeutic implications.     

Immunochemical characterization and radioimmunometric detection of molecules shed by human ovarian cancer

Monoclonal antibodies (MAbs) OC125, MOv2 and MOv8 recognize the CA125, CAMOv2 and CAMOv8 epitopes, respectively, which are associated with human ovarian carcinomas and are shed by these tumors. The biochemical analysis of the recognized antigens and epitopes has been performed to investigate the possibility of exploiting their expression, if any, on the same molecules. Cross-competition experiments clearly indicated that the 3 epitopes are distinct. Biochemical analysis was performed on a cyst fluid from an ovarian cystadenoma. Heat treatment and periodate oxidation indicated that CAMOv2 and CAMOv8 are saccharidic and suggested that CA125 is a conformational epitope to which both saccharides and the protein backbone could contribute. By gel-filtration chromatography CA125 activity was eluted into 2 peaks of high molecular weight, whereas CAMOv2 and CAMOv8 activities were associated with a single broad peak which included CA125-positive fractions. Isopycnic centrifugation showed that CA125, CAMOv2 and CAMOv8 carrying molecules had the same high density (1.46 g/ml) in the first peak, whereas CA125 molecules had a lower density (1.41 g/ml) in the second peak. Double-determinant immunoradiometric assays, carried out using different combinations of the MAbs, indicated that in the cyst fluid molecules expressing both CAMOv2 and CAMOv8 could be detected, whereas CA125 was carried by different molecules. CAMOv2 and CA125 could however be expressed on the same molecule in 2 out of 9 ascitic fluids from ovarian carcinoma patients. Taken together, these data indicate that CA125 and CAMOv2-CAMOv8 were only occasionally expressed on the same molecules. Therefore, the use of the CA125-CAMOv2 combination could not increase the sensitivity achievable by using each respective simultaneous immunoradiometric assay.     

Hyponatraemia in children with acute CNS disease: SIADH or cerebral salt wasting?

Hyponatraemia in patients with an acute central nervous system disease can be caused by two different mechanisms: (1) excretion of free water, i.e. the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) and (2) excessive sodium excretion, i.e., the cerebral salt wasting syndrome (CSW). Although the concept of CSW is well known in adult medicine, it is still not established in child neurology. We conducted a retrospective analysis of electrolyte disturbances in 195 children with various acute CNS diseases. In 20 children (10.3%) hyponatraemia with plasma sodium below 130 mmol/l was identified. On the basis of clinical and laboratory data 7 of these 20 children were diagnosed as having SIADH, and the other 9 children, as having CSW. Our data suggest that hyponatraemia attributable to CSW is at least as frequent in children as SIADH. Because of their different pathophysiological mechanisms, which require diametrically opposed therapeutic regimens, early differential diagnosis is mandatory if the correct treatment is to be given. Received: 10 March 2000 Revised: 21 July 2000     

Elimination of clonogenic tumor cells from human bone marrow using a combination of monoclonal antibody:ricin A chain conjugates

Effective autologous bone marrow transplantation for leukemia and lymphoma is likely to depend upon the selective removal in vitro of malignant cells from normal human bone marrow precursors. Highly specific cytotoxic conjugates formed by coupling ricin A chain to monoclonal antibodies might prove useful for the selective elimination of malignant cells. Consequently, ricin A chain conjugates have been prepared with several different murine monoclonal antibodies and tested for their ability to eliminate clonogenic Burkitt's lymphoma cells from an excess of human bone marrow. The most active reagents included an antibody:A chain conjugate which bound to the nonpolymorphic chain of the la molecule and another which reacted with the mu heavy chain of cell surface immunoglobulin. Conjugates formed with anti-common acute lymphoblastic leukemia antigen, anti-Mr 26,000 glycoprotein, and anti-B1 were much less active on these Burkitt's cells, contrasting with results of complement-dependent tumor cell lysis. Tumor cell kill was partially inhibited by the addition of greater than 2 X 10(6) human bone marrow cells/ml but could be potentiated by increasing the concentration of conjugate or by the addition of 10 mM ammonium chloride. In the presence of ammonium chloride, at least 4 logs of clonogenic tumor cells could be eliminated within 24 h from a 20-fold excess of bone marrow using 10(-7) M ricin A chain linked to one or two different antibodies. Similar treatment of normal human bone marrow temporarily inhibited granulocyte-macrophage colony-forming units (cell) formation but did not compromise establishment of continuous bone marrow cultures. The degree of selective elimination of tumor cells with A chain antibody conjugates was comparable to that achieved with 4-hydroperoxycyclophosphamide or with multiple monoclonal antibodies and complement.     

A comparison of polymerase chain reaction and an infectivity assay for human immunodeficiency virus type 1 titration during virus inactivation of blood components

Three examples of human plasma-derived concentrates, intermediate- purity factors VIII and IX, and fibrinogen were spiked with tissue culture-grown human immunodeficiency virus type 1 (HIV-1) strain RF. All examples were freeze-dried and heated at 80 degrees C for 72 hours by using validated production process models. HIV-1 infectivity was measured by a syncytial infectivity assay in C8166 cells and then compared with levels determined by nested HIV polymerase chain reaction (PCR). The infectivity assay demonstrated a reduction index of at least 4.5 log10, while PCR showed an average 1.7 log10. Large amounts of HIV- 1 RNA (10(5)) were still detectable by PCR in samples in which infectivity assays failed to detect any HIV-1. These data suggest that HIV-1 PCR levels do not parallel HIV-1 infectivity levels during virus- inactivation procedures involved in coagulation factor concentrate production. PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal.     

In vitro susceptibility of Bacillus anthracis to various antibacterial agents and their time-kill activity

OBJECTIVES: To investigate the in vitro acquisition of resistance to antibiotics by Bacillus anthracis. METHODS: The in vitro activities of 18 antibacterial agents against two strains of B. anthracis, the Sterne strain and the Russian anthrax vaccine strain ST-1, were tested by determining the MICs and by measuring the rates of antibiotic kill at 5x and 10x MIC. RESULTS: The fluoroquinolones ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin, the beta-lactams penicillin G and amoxicillin, the macrolide clarithromycin, the ketolide telithromycin, as well as clindamycin, rifampicin and quinupristin/dalfopristin had MICs in the range of 0.03-0.25 mg/L. Minocycline had an MIC of 0.03 mg/L, as did penicillin, against the ST-1 strain. Ciprofloxacin had an MIC of 0.03 mg/L against both strains. Erythromycin, vancomycin and the oxazolidinone linezolid were less active (MIC 0.5-2.5 mg/L). Ceftriaxone was the least active, having an MIC of 8.0 mg/L. Chloramphenicol was inactive (MIC > 256 mg/L). Quinupristin/dalfopristin, rifampicin and moxifloxacin showed the most rapid bacterial killing, achieving a complete eradication of detectable organisms (2 log(10) reduction within 0.5-3 h and 4 log(10) reduction within 0.5-4 h for both strains at concentrations of 5x and 10x the MIC). The beta-lactams and vancomycin demonstrated a 2-4 log(10) reduction within 5-15 h. Ceftriaxone had a similar effect to penicillin and amoxicillin against the ST-1 strain, but a slower effect than these two beta-lactams against the Sterne strain. The macrolides, tetracyclines and linezolid demonstrated a lower kill rate, while chloramphenicol did not kill at all. CONCLUSIONS: These data expand on the spectrum of agents recommended for the treatment of anthrax (ciprofloxacin, penicillin G and tetracyclines) and add new options, such as other fluoroquinolones, amoxicillin, rifampicin and quinupristin/dalfopristin, as potential therapeutic agents.