Clinical outcome of pretreated B-cell chronic lymphocytic leukemia following alemtuzumab therapy: a retrospective study on various cytogenetic risk categories.

BACKGROUND: Patients with B-cell chronic lymphocytic leukemia (CLL) with 17p deletion respond poorly to chemotherapy. This retrospective study evaluated the benefit of alemtuzumab monotherapy in unselected patients with advanced CLL in the various cytogenetic subgroups. PATIENTS AND METHODS: Data were collected from 105 consecutive, pretreated, cytogenetically defined patients who had received alemtuzumab. Response, progression-free survival (PFS), and overall survival (OS) were assessed. RESULTS: The hierarchic incidence of cytogenetic abnormalities was: 13q deletion (as sole abnormality), 18%; trisomy 12, 13%; 11q deletion, 19%; 17p deletion, 33%; and none of these, 16%. Overall response rate (ORR) was 43% in the total cohort and 49% in the subgroup of 17p-deleted patients (n = 35). From the start of alemtuzumab monotherapy, median PFS in the total cohort and in the subgroup of 17p-deleted patients was 7.0 and 7.1 months, respectively. Median OS in the total cohort and in 17p-deleted patients was 32.8 and 19.1 months, respectively. The poor-risk group of patients with CLL (i.e. fludarabine resistant, 17p deletion; n = 20) showed encouraging ORR, PFS, and OS (35%, 7.0 and 19.2 months, respectively). CONCLUSIONS: Alemtuzumab was effective in treating patients with CLL across the cytogenetic categories evaluated, but there were differences. In patients with CLL with 17p deletion quite favorable ORR, PFS, and OS were achieved.

Two Drosophila melanogaster proteins related to intermediate filament proteins of vertebrate cells.

Monoclonal antibodies were prepared against a 46,000 mol wt major cytoplasmic protein from Drosophila melanogaster Kc cells. These antibodies reacted with the 46,000 and a 40,000 mol wt protein from Kc cells. Some antibodies showed cross-reaction with 55,000 (vimentin) and 52,000 mol wt (desmin) proteins from baby hamster kidney (BHK) cells that form intermediate sized filaments in vertebrate cells. In indirect immunofluorescence, the group of cross reacting antibodies stained a filamentous meshwork in the cytoplasm of vertebrate cells. In Kc cells the fluorescence seemed to be localized in a filamentous meshwork that became more obvious after the cells had flattened out on a surface. These cytoskeletal structures are heat-labile; the proteins in Kc or BHK cells rearrange after a brief heat shock, forming juxtanuclear cap structures.

The relationship of plasma guanethidine levels to adrenergic blockade.

Seventeen hypertensive patients receiving guanethidine for therapy were studied to determine the relationship of guanethidine plasma levels to adrenergic blockade. Plasma levels of guanethidine were measured by gas chromatography-mass spectrometry, and adrenergic blockade was defined by determining the venous reflex response to Valsalva maneuver or deep breath. A significant correlation was found between the change in the venous reflex response and the fall in mean standing pressure when guanethidine is given to patients maintained on a sodium restricted diet. A linear relationship was found between dose and plasma guanethidine concentration (p less than 0.0001), but there was a 6-fold interindividual variation in the plasma levels resulting from any given dose. Adrenergic blockade occurred when plasma levels were 8 ng/ml or higher. These results indicate that the large individual variation in dose requirements for the hypotensive effects of guanethidine most likely is not due to requirements for greatly different plasma levels of the drug; that the variation must result from pharmacokinetic determinants of differing plasma levels between individuals or from other factors, such as increased plasma volume, which maintain elevated arterial pressure in the face of adrenergic blockade.

Deletion of the myristylation signal allows high-level production of the hepatitis B virus large surface glycoprotein preS1 with vaccinia virus recombinants.

We have investigated the requirements necessary for high-level production of the hepatitis B virus (HBV strain ayw) large surface glycoprotein preS1 with vaccinia virus (VV) recombinants. In earlier studies, only nanogram amounts of preS1 could be obtained from cells infected with an appropriate recombinant VV carrying the preS1 gene under the transcriptional control of a conventional VV promoter (p7.5). Here, we report that the use of an improved promoter system, i.e., the bacteriophage T7 polymerase/VV hybrid expression system (T7/EMC system) in combination with a G-C conversion at position 5 of the preS1 open reading frame, deleting the myristylation motif of the polypeptide, results in an at least 12-fold increase in preS1 expression compared to the wild-type preS1 expressed with the strongest homologous VV promoter system known so far. Although the T7/EMC promoter system was most effective, improved expression of the modified preS1 (preS1dMyr) is independent from the promoter system used, from the insertion locus of the modified preS1 within the VV genome and also from the cell line used for expression studies.

Characterization of the vaccinia MVA hemagglutinin gene locus and its evaluation as an insertion site for foreign genes.

The 'Modified Vaccinia Ankara' (MVA) strain is a potential live vaccine vector. The use of the hemagglutinin (ha) gene of the MVA strain as an insertion site for foreign genes was evaluated. To identify the molecular basis of the hemagglutinin-negative (HA-) phenotype of MVA, the ha gene and the region around this gene were sequenced. Amino acid (aa) sequence comparisons with functional hemagglutinins of other vaccinia strains predicted a functional polypeptide. The late part of the promoter region of the ha gene, however, was deleted, causing the apparent loss of the ha gene function. Nevertheless, insertion of foreign DNA into the ha gene allowed generation of functional recombinant viruses, indicating that the ha-gene region is a suitable insertion site.

Vaccinia viral/retroviral chimeric vectors.

Retroviral vectors have become important tools in gene therapy due to a number of desirable properties, including efficient gene delivery and stable genomic integration. Some shortcomings, however, still remain to be solved. Retroviral vectors cannot be grown to as high titers as for example adenoviruses or vaccinia viruses, they tend to be unstable and are sensitive to lysis by complement when transfused into patients. The search for more robust retroviral delivery systems has led to the development of hybrid viral vectors trying to combine the broadly estimated features of retroviral vectors with advantageous properties of a second viral vector system. Chimeric systems with retroviruses and adeno-alphavirus and herpesviruses have been reported. This review is dedicated to vaccinia virus, a widely used vector in molecular and cell biology, as a chimeric carrier for retroviral vector units. In the first poxviral/retroviral constructs, retroviral vector units integrated into a defective vaccinia vector, gave rise to transduction competent particles. Due to the high insertion capacity of the vaccinia system, also the packaging components could be inserted into the carrier virus resulting in a system that is independent of retroviral packaging cell lines. Moreover, since vaccinia is a cytoplasmic virus that does not recognize nuclear transcription and processing signals, retroviral vectors with introns and internal transcription stops could be constructed that transduce complex gene cassettes. The topic of this review is the vaccinia viral / retroviral vector system and possible applications to gene therapy.

Discovery of the hemifumarate and (alpha-L-alanyloxy)methyl ether as prodrugs of an antirheumatic oxindole: prodrugs for the enolic OH group.

Ether, ester, and carbonate derivatives of the antirheumatic oxindole 1 were prepared and screened as potential prodrugs of 1. This effort led to the discovery of the (alpha-L-alanyloxy)-methyl ether and hemifumarate derivatives of 1 which deliver the drug efficiently into the circulation of test animals, are stable in the solid state, and possess good stability in solution at low pH as required to ensure gastric stability. Success in achieving acceptable bioavailabilities of 1 across species (rats, dogs, and monkeys) followed the inclusion of ionizable functionality within the promoiety to compensate for masking the polar enolic OH group of the free drug. However, the introduction of ionizable functionality was often associated with decreased stability, as demonstrated by the hemisuccinate, hemiadipate, hemisuberate, and alpha-amino ester derivatives of 1 which could not be isolated. A clear exception was the hemifumarate derivative of 1 which was not only isolable but actually more stable at neutral pH than the nonionizable ester analogues. The solution and solid state stability of the hemifumarate, together with its activity as a prodrug of 1, suggests that hemifumarate be considered as an alternative to hemisuccinate as a prodrug derivative for alcohols, particularly in situations where solution state stability is an issue.

High level expression of active human prothrombin in a vaccinia virus expression system.

We have worked out an efficient and time saving procedure for the expression of recombinant human prothrombin. The glycoprotein was expressed in the vaccinia virus expression system in several mammalian cell lines. The kidney cell lines Vero and BHK and the human cell line Hela were found to efficiently secrete prothrombin. Expression level of 3-4 micrograms of factor II per 10(6) cells per day corresponding to 18-23 mU per 10(6) cells per day were achieved. Since the expression levels obtained with the vaccinia virus/Vero cell system were comparable to those obtained in amplified transformed CHO cells it provides an alternative system for the efficient expression of human prothrombin and may allow to further elucidate structure-function relationships of (pro)thrombin and its various effectors.

High expression of a B-domain deleted factor VIII gene in a human hepatic cell line.

The expression of a modified human coagulation factor VIII cDNA in a human liver-derived cell line is described. A B-domain deleted FVIII (rVIIIdB928) cDNA controlled by a strong viral promoter/enhancer was linked to a dominant selection-/amplification marker and transfected into the human hepatic cell line SK-HEP-1. By means of this system, up to 3.5 U rFVIIIdB928/10(6) cells x 24 h could be detected immediately after selection without gene amplification. This level is orders of magnitude higher than that obtained in Chinese hamster ovary (CHO) f1p4s under the same conditions. Efficient expression of rFVIIIdB928 in SK-HEP-1 cells was temperature dependent, a 4-fold higher level of activity was achieved in culture supernatants at decreased incubation temperatures of 28 degrees C. This system allows the production of high amounts of recombinant rFVIIIdB928 without time and labour consuming gene amplification procedures.

Recombinant human factor X: high yield expression and the role of furin in proteolytic maturation in vivo and in vitro.

Factor X/Xa plays a pivotal role in the coagulation cascade and exhibits a therapeutic potential for the treatment of factor X-deficient as well as FVIII and FIX inhibitor patients. This report describes the establishment of Chinese hamster ovary cell clones expressing recombinant human factor X up to 120 microg/mL x day and 78 microg/10(6) cells x day, that is to 100-fold higher levels than reported previously. Although propeptide removal and single chain precursor to light and heavy chain processing as well as vitamin K-dependent gamma-carboxylation became impaired at these expression levels, up to 25% of the recombinant human factor X produced was active. This represents the highest functional activity ever reported for a vitamin K-dependent protein at such an expression level. Expression of recombinant human factor X in Chinese hamster ovary cells lacking the endoprotease Furin revealed that propeptide removal still occurred, whereas single chain precursor to light/heavy chain processing was abolished. This suggests that a protease different from Furin mediates propeptide removal, a unique finding compared with the other vitamin K-dependent coagulation factors. In contrast, exposure of incompletely processed rFX molecules to soluble recombinant Furin in vitro mediated both of these cleavage reactions despite the absence of a typical argP4-xP3-lys/argP2-argP1 Furin cleavage site in the propeptide, indicating relaxed specificity in vitro. Concomitantly with the degree of processing, the functional activity of recombinant human factor X increased. Interestingly, Furin was shown to even perform correct N-terminal proteolytic trimming of FX molecules truncated amino-terminal to the P3 residue in vitro. Depending on the absence or presence of warfarin in the culture media, as well as on the processing state, four distinct recombinant human factor X light chain isoforms were observed and their structure characterized. One of these light chain forms correlated with the functional activity. Finally, the distribution of the individual light chain isoforms suggests that gamma-carboxylation may be a prerequisite for propeptide removal.

Early postnatal growth evaluation in full-term, preterm and small-for-dates infants.

Postnatal growth patterns of weight, length/height and head circumference in full-term (FTI), preterm (PTI) and small-for-dates (SFDI) infants, are described by using distance and velocity data together with the concept of growth per unit of body weight. The study was performed in 112 healthy Caucasian infants, of a similar socioeconomic status, in Montevideo, Uruguay. Median growth velocity (MGV) and median growth velocity per unit (MGVU) of body size are defined. The authors stress that: (a) growth velocity is related to body mass, (b) a useful evaluation of growth is made by using two consecutive measures with a certain time interval independently of birthweight and gestational age, and (c) expressing growth per day per unit relates well to daily nutritional and other requirements.

Ultrasonography and fetal growth: key perinatal factors.

To assess whether children can be predetermined prenatally to be either normally or abnormally grown and what the relationships are between intrauterine growth retardation and postnatal growth, we undertook a longitudinal study of fetal growth measuring fetuses ultrasonically. We measured 257 fetuses antenatally for femur length, biparietal diameter, head circumference (by formula calculation), abdominothoracic diameter, and body weight (by formula calculation). We chose femur length because it can be measured fairly accurately from 15 weeks' gestation to term and would represent linear growth. We noted that there is a peak length velocity before 15 weeks' gestation. In 61 fetuses, we found that by measuring the femur length within 1 week before birth, plotting that femur length against the total length measured when the baby is newly born, and multiplying the femur length by 7.0538, we derived a good estimate of total body length, with a small SD of +/- 0.0493. Thus we indicate that multiplying femur length by 7 during the second half of gestation gives a good indication and prediction of total fetal and neonatal length. Further, assessment of postnatal growth by examination of the prenatal length distance data from 15 weeks to term for femur length, and assessment of the body length of these subjects as infants from birth to 2 postnatal years, showed that the velocity curves of both phases steadily decelerate until 2 years. Also, predictive curves for fetal weight were constructed by use of Hadlock's formula for estimating fetal weight from fetal femur length and head and body measurements. It appeared that adding one biparietal diameter to the abdominothoracic diameter measurement and femur length is a better prognosticator for small-for-gestational-age infants than any measurement alone.

A systematic and quantitative analysis of PCR template contamination.

A quantitative and systematic analysis is provided for ubiquitously present template DNA interfering with the quantification of human DNA by PCR. Two sources contributing to DNA background were identified. The first one is interpreted as DNA present in chemicals and on equipment and the second as caused by operator handling. The amounts were equivalent to 2.5 and 8.9 pg per mL of sample, and the estimated frequencies of contamination were 65 and 35%, respectively, resulting in an effective limit of detection of 17.4 pg/mL. Below this level--named effective laboratory background--a result could not be considered as authentic. Knowledge of these parameters is important for laboratories that analyze minute amounts of human DNA by PCR for purposes such as quantification, typing, and sequencing.

Normal growth and development: current concepts.

Human growth and development are a continuum starting at conception. Prenatal growth can only be estimated at present but is an important consideration in an evaluation of a child's developmental status. Postnatal growth can be assessed for size attained (distance curve) or change over time (velocity curve). Velocity curves truly reflect the pattern of growth in stature.