Similar characteristics of the CDR3 of V(H)1-69/DP-10 rearrangements in normal human peripheral blood and chronic lymphocytic leukaemia B cells

The variable heavy chain (V(H)) gene segment V(H)1-69/DP-10 has been shown to be over-represented in B-cell chronic lymphocytic leukaemia (CLL). Because of certain similar characteristics of their complementarity determining region 3 (CDR3), including preferential utilization of J(H)6 elements and an extended length, it has been suggested that antigenic stimulation might be involved in leukaemogenesis. Utilizing single-cell PCR to amplify and sequence genomic DNA from individual normal human peripheral blood B cells, we have obtained 7/421 productively and 1/69 nonproductively rearranged V(H) genes that used V(H)1-69/DP-10. All productive rearrangements were unmutated, used J(H)6 and had an average CDR3 length similar to that previously found in V(H)1-69/DP-10-expressing CLL cells. These results suggest that CLL may arise from B cells commonly found in the peripheral B-cell repertoire and do not represent expansion of a unique subset of specific antigen-reactive B cells.     

Immunisation with recombinant AMA-1 protects mice against infection with Plasmodium chabaudi

The Plasmodium merozoite surface antigen apical membrane antigen-1 (AMA-1) has previously been shown to provide partial protection to Saimiri and rhesus monkeys immunised with recombinant Plasmodium fragile or parasite-derived Plasmodium knowlesi AMA-1, respectively. In the study reported here we have used the Plasmodium chabaudi/mouse model system to extend our pre-clinical assessment of an AMA-1 vaccine. We describe here the expression of the full-length Plasmodium chabaudi adami AMA-1 and the P. chabaudi adami AMA-1 ectodomain using both baculovirus and Escherichia coli. The ectodomain expressed in E. coli, which contained an N-terminal hexa-his tag, was purified by Ni-chelate chromatography and refolded in vitro in the presence of oxidised and reduced glutathione to generate intramolecular disulphide bonds. In a series of vaccine trials, in both inbred and outbred mice, highly significant protection was obtained by immunising with the refolded AMA-1 ectodomain. Protection was shown to correlate with antibody response and was dependent on intact disulphide bonds. Passive transfer of antibodies raised in rabbits against the refolded AMA-1 ectodomain was also protective. In view of this demonstration that E. coli expression of a soluble P. chabaudi AMA-1 domain can generate a vaccine that is effective in mice, we are pursuing a similar approach to generating a vaccine against P. falciparum for testing in human volunteers.     

Molecular genetics of peroxidase deficiency

Myeloperoxidase (MPO) belongs to a family of related proteins which also includes eosinophil, thyroid, and lactoperoxidase. The MPO gene is a 14-kb gene located on the long arm of chromosome 17. Thus far four mutations (R569W, Y173C, M251T and a 14-base deletion in exon 9) have been identified in patients with MPO deficiency. As in other genetically determined diseases, many more mutations will eventually be revealed that cause this disease. Present evidence shows that most patients are compound heterozygotes, i.e., they have inherited different mutations on their paternal and maternal MPO alleles. Understanding why some patients with this genetic deficiency develop clinical symptoms while others do not requires mutation analyses of a large number of patients. This includes the analysis of genotype-phenotype relationships. Genotyping has also been started in patients with EPO-deficiency.     

Comparative pharmacodynamics of CYP2B induction by DDT, DDE, and DDD in male rat liver and cultured rat hepatocytes

In this study the pharmacodynamics were characterized of rat hepatic cytochrome P-450 2B (CYP2B) induction by the pesticide DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], which is bioretained, and DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane], which is metabolized further and therefore less prone to bioaccumulate. DDT, DDE, and DDD were each found to be pure phenobarbital-type cytochrome P-450 inducers in the male F344/NCr rat, causing induction of hepatic CYP2B and CYP3A, but not CYP1A. The ED50 values for CYP2B induction (benzyloxyresorufin O-dealkylation) by DDT, DDE, and DDD were, respectively, 103, 88, and > or = 620 ppm in diet (14 d of exposure). The efficacies (Emax values) for induction of benzyloxyresorufin O-dealkylation by DDT, DDE, and DDD were 24-, 22-, and > or = 1-fold, respectively, compared to control values. The potencies of the three congeners for CYP2B induction appeared also to be similar, with EC50 values (based on total serum DDT equivalents) of 1.5, 1.8, and > or = 0.51 microM, respectively. The EC50 values based on DDT equivalents in hepatic tissue were 15, 16, and > or = 5.9 micromol/kg liver tissue, respectively. In primary cultures of adult rat hepatocytes, DDT, DDE, and DDD each displayed ability to induce total cellular RNA coding for CYP2B (ED50 values of 0.98, 0.83, and > or = 2.7 microM, respectively). These results suggest that DDT, DDE, and DDD each possess a high degree of intrinsic CYP2B-inducing ability for rat liver, despite marked differences in bioretention among the congeners.     

Mechanistic comparison of artificial-chaperone-assisted and unassisted refolding of urea-denatured carbonic anhydrase B

The serine protease thrombin is a key enzyme in the control of blood coagulation and displays numerous other effects on platelet, endothelial and smooth muscle cell function. The pre-eminence of thrombin in the coagulation cascade has made the enzyme a popular drug target in the search for more clinically acceptable and safe anti-coagulants. This concept has been particularly strengthened by the demonstration that direct inhibitors of thrombin such as Revasc are clinically effective. A number of low molecular weight thrombin inhibitors have now been described in the literature although to date because of their inherent low bioavailability compounds have been limited to the parenteral route of administration. The introduction of appropriate pharmacokinetic properties into these first generation thrombin inhibitors has been problematic despite intensive research in this area. However, the first pre clinical examples of direct thrombin inhibitors possessing good oral bioavailability is now emerging. This review updates current developments in the progress towards the discovery of orally available thrombin inhibitors and suggests that the first clinical validation of drugs from this field is imminent.     

A comparison of hemodynamic parameters derived from transthoracic electrical bioimpedance with those parameters obtained by thermodilution and ventricular angiography

OBJECTIVE: To determine the limits of agreement between the cardiac output and volumetric data estimated by impedance cardiography with the cardiac output determined by thermodilution and the left ventricular ejection fraction and end-diastolic volume estimated from left ventriculography. DESIGN: A prospective study. SETTING: The cardiac catheterization laboratory of a university-affiliated teaching hospital. PATIENTS: Twenty-four patients with coronary artery disease undergoing elective left- and right heart catheterization. INTERVENTIONS: Cardiac output was measured by the thermodilution method and the ejection fraction and left ventricular volumetric data were determined by ventriculography. These same measurements were obtained by simultaneously performed impedance cardiography using a commercially available bioimpedance device. MEASUREMENTS AND MAIN RESULTS: The patients' mean cardiac output was 4.6 +/- 1.7 L/min by bioimpedance and 5.0 +/- 1.1 L/min by thermodilution. The limits of agreement between the two methods was -4.1 to 3.5 L/min. The 95% confidence intervals for the lower and upper limits of agreement were -2.7 to -5.5 L/min and 2.1 to 4.9 L/min, respectively. The mean ejection fraction was 63 +/- 8% by bioimpedance and 53 +/- 15% by ventriculography. The limits of agreement between the ejection fraction estimated by bioimpedance and ventriculography was -35% to 37%. The 95% confidence intervals for the lower and upper limits of agreement were -22% to -48% and 24% to 50%, respectively. The mean left ventricular end-diastolic volume was 108 +/- 47 mL, as estimated by bioimpedance, and 121 +/- 35 mL, as estimated by ventriculography. The limits of agreement between the left ventricular end-diastolic volume as estimated by bioimpedance and ventriculography was -139 to 113 mL. The 95% confidence intervals for the lower and upper limits of agreement were -184 to -94 mL and 68 to 158 mL, respectively. CONCLUSIONS: The 95% confidence range defining the limits of agreement between cardiac output and volumetric data estimated by bioimpedance, with the cardiac output measurement by thermodilution and the volumetric data estimated from left ventriculography, were wide, making the degree of agreement clinically unacceptable. In the opinion of the authors, impedance cardiography should not replace invasive hemodynamic monitoring at this time.     

Rare origin of a retroperitoneal mass: Castleman's disease

Castleman's disease (angiofollicular hyperplasia of the lymphatic nodes) can exceptionally appear as a retroperitoneal mass of difficult differential diagnosis relative to other malignant retroperitoneal masses. Because of its rarity, one case report of a retroperitoneal mass with histologic study corresponding to Castleman's disease is contributed. A revision of the different histologic varieties of Castleman's disease, specific treatment and prognosis is included.     

Perineural spread of cutaneous squamous cell carcinoma manifesting as ptosis and ophthalmoplegia (orbital apex syndrome)

This paper reports two cases of orbital apex syndrome. The most salient clinical signs, ophthalmoplegia and eyelid ptosis, arose from perineural spread of facial squamous cell carcinomas that were previously excised with tumour-free surgical margins and exhibited no signs of local or other regional recurrence. The interest of these two cases lies in the fairly rare occurrence of this type of tumour spread and the highly aggressive nature of the tumour, unequivocal diagnosis of which usually arrives too late for a surgical solution. Awareness of the possibility of such perineural spread may allow the clinician to establish an early diagnosis and thus undertake radical surgery, thereby increasing the likelihood of success in combination with postoperative radiotherapy.