Further characterization of cyclophosphamide resistance: expression of CD95 and of bcl-2 in a CML cell line

Drug resistance is a common cause of treatment failure in oncology. In addition to the resistance caused by over-expression of p-glycoprotein and similar molecules other mechanisms are involved in the selection or induction of drug resistant tumor cells. In this study, we characterized a CML cell line made resistant to cyclophosphamide (KBM7-B5-1803) further for the expression of apoptosis promoting and inhibiting molecules. We found that KBM7-B5-1803 has a 3 4-fold over-expression of the receptor CD95 (Fas/Apo-1) compared with the parent line. The regulation of CD95 by cytokines was comparable to other types of cells. Despite the inducibility and over-expression of CD95, CD95 failed to trigger apoptosis in both the parent and the drug resistant line. The drug resistant line has a particular pattern of the expression of bcl-2 family members: bcl-2 protein and message were expressed to a similar extent, however, compared with the parent line, the message for bclx short was decreased. P-glycoprotein was not expressed in either cell line. Taken together we show here in a leukemia cell line that the phenotype of cyclophosphamide resistance is associated with a particular pattern of apoptosis-related molecules.     

Evaluation of low density spine software for the assessment of bone mineral density in children

Pediatric dual-energy X-ray absorptiometry spine scans often cannot be analyzed with standard software due to a failure to identify the bone edges of low density vertebrae. Low density spine (LDS) software improves bone detection compared with standard software. The objective of this study was to compare bone mineral density (BMD) measurements obtained with the standard and LDS software in 27 healthy nonobese, 32 obese, and 41 chronically ill children, ages 2-18 years. Lumbar spine (L1-L4) BMD, measured by standard analysis, ranged from 0.531-1.244 gm/cm2. Reanalysis with the LDS software resulted in a systematic increase (mean +/- SD) in estimated bone area of 17.0+/-5.0%, an increase in bone mineral content of 6.1+/-6.3%, and a mean decrease in BMD of 8.7+/-1.7% (all p < 0.001). This resulted in a mean decrease in BMD Z score of 0.7+/-0.2. Linear regression models, predicting standard BMD from LDS BMD, were fit for the three subject groups (R2 = 0.993-0.995). Small differences in slopes were detected across groups (p = 0.07); LDS BMD predicted higher standard BMD in obese subjects. In conclusion, LDS analysis resulted in a clinically significant decrease in measured BMD. The association between analysis methods was exceptionally high (R2 > 0.99), indicating that LDS BMD accurately predicts standard BMD. Although LDS BMD in obese subjects predicts higher standard BMD results than in nonobese subjects, the small difference is of questionable clinical significance. LDS software is a useful tool for the assessment of BMD in children.     

Management of rhesus isoimmunization by preimplantation genetic diagnosis

Intracranial osteolipomas are rare lesions which occur in the region of the tuber cinereum. All cases reported to date have been incidental autopsy findings. We describe a patient who presented with a variety of neurological symptoms and had a typical osteolipoma surgically removed.     

A retrospective study of changes in physical symptoms and body image after reduction mammaplasty

Reduction mammaplasty is performed typically to alleviate the painful physical symptoms of macromastia. Women who suffer from macromastia also frequently present to the plastic surgeon with heightened body image dissatisfaction and maladaptive behavioral changes in response to their breast size. Numerous investigations have demonstrated improvement in physical symptoms after breast reduction surgery. Studies have also suggested that psychological improvement occurs postoperatively; however, they have not used well-validated, standardized psychological measures. The present study is a retrospective analysis of the physical and psychological status of women who underwent reduction mammaplasty. One hundred ten patients who underwent a reduction mammaplasty between 1982 and 1996 were mailed a packet of questionnaires designed to assess current physical symptoms and body image. Sixty-one of the 110 patients (55 percent) responded. The vast majority reported substantial improvement or elimination of neck, back, shoulder, and breast pain, grooving from bra straps, poor posture, skin irritation, and social embarrassment. In addition, they reported significantly less dissatisfaction with their breasts as compared with a sample of breast reduction patients assessed preoperatively. Symptom relief and improved body image occurred independently of preoperative body weight, as we found few significant differences between obese and non-obese women concerning the resolution of physical symptoms or improvement in body image. Results provide further evidence of the efficacy of reduction mammaplasty not only for relief of physical symptoms but also for alleviation of body image dissatisfaction.     

Novel antitumor 2-cyanoaziridine-1-carboxamides

A set of 20 2-cyanoaziridine-1-carboxamides was synthesized from 2-cyanoaziridine and appropriate isocyanates. These compounds were active against a variety of solid and hematological tumor cells in culture, including strains resistant to doxorubicin and mitoxantrone. Their potencies in these assays correlated with the lipophilicity of substituents. The N-phenyl derivative was more potent and equally effective to imexon, a cyclized 2-cyanoaziridine-1-carboxamide of clinical interest, against cloned fresh human tumors.     

Directed mutagenesis studies of the metal binding site at the subunit interface of Escherichia coli inorganic pyrophosphatase

Recent crystallographic studies on Escherichia coli inorganic pyrophosphatase (E-PPase) have identified three Mg2+ ions/enzyme hexamer in water-filled cavities formed by Asn24, Ala25, and Asp26 at the trimer-trimer interface (Kankare, J., Salminen, T., Lahti, R., Cooperman, B., Baykov, A. A., and Goldman, A. (1996) Biochemistry 35, 4670-4677). Here we show that D26S and D26N substitutions decrease the stoichiometry of tight Mg2+ binding to E-PPase by approximately 0.5 mol/mol monomer and increase hexamer stability in acidic medium. Mg2+ markedly decelerates the dissociation of enzyme hexamer into trimers at pH 5.0 and accelerates hexamer formation from trimers at pH 7.2 with wild type E-PPase and the N24D variant, in contrast to the D26S and D26N variants, when little or no effect is seen. The catalytic parameters describing the dependences of enzyme activity on substrate and Mg2+ concentrations are of the same magnitude for wild type E-PPase and the three variants. The affinity of the intertrimer site for Mg2+ at pH 7.2 is intermediate between those of two Mg2+ binding sites found in the E-PPase active site. It is concluded that the metal ion binding site found at the trimer-trimer interface of E-PPase is a high affinity site whose occupancy by Mg2+ greatly stabilizes the enzyme hexamer but has little effect on catalysis.