Docetaxel as single-agent treatment in elderly patients with advanced breast cancer

OBJECTIVE

To assess the efficacy and safety profile of docetaxel, as a single agent, in the treatment of elderly patients with advanced breast cancer.

METHODS

Twenty-eight patients, with a median age of 72 (range 66-84) years, were included in the study and received docetaxel (50-100 mg/m(2)) every 3-4 weeks as first- or second-line treatment of advanced breast cancer. Granulocyte colony-stimulating factor (G-CSF) was administered as primary prophylaxis in 97% of cycles.

RESULTS

The overall response rate was 50% (95% CI 32, 69). The median time to disease progression was 10.7 months (95% CI 10.0, 11.5), and the median overall survival was 26.6 months (95% CI 16.6, 36.7). Neutropenia was the most frequent grade 3/4 toxicity (18% of patients and 5% of cycles). There was just one case of febrile neutropenia that resulted in toxic death. Severe neutropenia only occurred in patients who did not receive G-CSF support from the start of the study treatment. Vomiting was the most frequent grade 3/4 non-haematological toxicity (11% of patients and 2% of cycles).

CONCLUSION

Docetaxel as a single agent is active in elderly patients with advanced breast cancer. The use of prophylactic G-CSF allowed the administration of high doses of docetaxel with minimal myelosuppression.

Analysis of tissue bioimpedance as a measurement of liver steatosis: experimental model in large animals

BACKGROUND

Electrical bioimpedance (BI) has been used to indirectly measure steatosis. This method has not yet been established in the clinics thus experimental studies are needed in big animals. We assessed BI to measure liver steatosis in porcine animals.

METHODS

Twelve large-white × Landrace pigs weighing 35 kg were allocated to a study (n = 9) and a control group (n = 3). A special diet was used to promote steatosis among the study group: methionine deficient and choline-restricted diet that contains supplements of cholesterol, collate and excess of saturated fat. Control group animals were fed a normal diet. A new tetrapolar electrode model was used for BI measurement, which were performed during open laparotomy by inserting a probe into one of the lobes. Measurements were done in the third and fourth segments of the pig liver, placing the probe either on the surface or inserted into the parenchyma of the liver. Open biopsies were obtained at the end of the measurements. Histological samples were processed and stained with hematoxylin-eosin to estimate macrosteatosis. Pearson correlation coefficient between BI and percentage steatosis were calculated at different frequencies.

RESULTS

After 4 months of the special diet all the animals in the study group developed steatosis (90% to 20%), whereas none of the control group was affected. Pearson correlation coefficients between BI and percentage of steatosis were significant (0.877-0.878) with the best correlations obtained with a probe placed on the fourth segment of the liver surface and the best frequency to perform the measurements being 50 and 75 kHz.

CONCLUSIONS

BI is an accurate, fast method for steatosis measurements, that is easier and cheaper than either open or needle biopsy.

Transition-metal-substituted indium thiospinels as novel intermediate-band materials: prediction and understanding of their electronic properties

Results of density-functional calculations for indium thiospinel semiconductors substituted at octahedral sites with isolated transition metals (M=Ti,V) show an isolated partially filled narrow band containing three t2g-type states per M atom inside the usual semiconductor band gap. Thanks to this electronic structure feature, these materials will allow the absorption of photons with energy below the band gap, in addition to the normal light absorption of a semiconductor. To our knowledge, we demonstrate for the first time the formation of an isolated intermediate electronic band structure through M substitution at octahedral sites in a semiconductor, leading to an enhancement of the absorption coefficient in both infrared and visible ranges of the solar spectrum. This electronic structure feature could be applied for developing a new third-generation photovoltaic cell.

Transcription of the Escherichia coli dcw cluster: evidence for distal upstream transcripts being involved in the expression of the downstream ftsZ gene

Escherichia coli strains VIP596 and VIP597 have been constructed to compare the amount of transcription of the ftsZ gene derived from proximal promoters in the ddlB-ftsZ region with that originating in the upstream regions of the dcw cluster. Both strains have in common a beta-galactosidase reporter fusion located at the ddlB locus, but differ in that VIP597 has a transcription terminator Omega interposon located downstream from lacZ. In addition, these strains have the ddlB, ftsQ, ftsA and ftsZ genes under the control of the IPTG-inducible promoter P(tac), allowing to control artificially ftsZ expression for normal cell division to take place. When beta-galactosidase activity was measured in VIP596 and VIP597 and compared to the levels measured in strain VIP407, in which the lacZ reporter fusion is located in the ftsZ gene, they were found to account for nearly 66% of the total transcription entering into ftsZ. This result indicates that the reduction in ftsZ transcription observed when the promoters in the ddlB-ftsA region are disconnected from the upstream sequences of the dcw cluster (as observed by Flärdh et al., Mol. Microbiol. 30 (1998) 305-316) in strain VIP490) is the direct consequence of the interruption in the transcription originated upstream and not due to the effect of such sequences on the promoters proximal to ftsZ.

Effect of extra aeration on extracellular enzyme activities and ATP concentration of dairy Pseudomonas fluorescens

The effect of forced aeration on extracellular enzyme synthesis during batch growth of a Pseudomonas fluorescens strain of dairy origin on pyruvate mineral salts medium at 7 degrees C was studied. Measurement of oxygen tension, electron micrographs to estimate cell volume, luciferase determination of ATP and plate counts were performed in the course of incubation. Cells from the stationary phase of growth had lower energy status (in terms of intracellular ATP concentration) in the cultures receiving surplus aeration. Those cells produced three times more extracellular proteinase and lipase than control cells. Onset time for production of both enzymes coincided with a sharp fall of intracellular ATP levels.

Cell division genes ftsQAZ in Escherichia coli require distant cis-acting signals upstream of ddlB for full expression

A transcriptional reporter fusion has been introduced into the chromosomal ftsZ locus in such a way that all transcription that normally reaches ftsZ can be monitored. The new Phi(ftsZ-lacZ ) fusion yields four times more beta-galactosidase activity than a ddlB-ftsQAZ-lacZ fusion on a lambda prophage vector. A strongly polar ddlB ::Omega insertion prevents contributions from signals upstream of the ftsQAZ promoters and decreases transcription of the chromosomal Phi(ftsZ-lacZ ) fusion by 66%, demonstrating that around two-thirds of total ftsZ transcription require cis-acting elements upstream of ddlB. We suggest that those elements are distant promoters, and thus that the cell division and cell wall synthesis genes in the dcw gene cluster are to a large extent co-transcribed. The ddlB ::Omega insertion is lethal unless additional copies of ftsQA are provided or a compensatory decrease in FtsZ synthesis is made. This shows that ddlB is a dispensable gene, and reinforces the critical role of the FtsA/FtsZ ratio in septation. Using the new reporter fusion, it is demonstrated that ftsZ expression is not autoregulated.

Dependency of Escherichia coli cell-division size, and independency of nucleoid segregation on the mode and level of ftsZ expression

Expression of ftsZ in strain VIP205 is dissociated from its natural promoters, and is under the control of an inducible tac promoter. This abolishes the oscillation in ftsZ transcription observed in the wild type, allowing different levels of ftsZ expression. We demonstrate that this construction does not affect the expression of other genes, and has no effects on replication or nucleoid segregation. A shift in IPTG from 30 microM, that supports division at wild-type sizes, to lower (6 microM) or higher (100 microM) concentrations, indicates that VIP205 cells can divide within a broad range of FtsZ concentrations. Analysis of the morphological parameters during the transition from one IPTG concentration to another suggests that the correct timing of ftsZ expression, and the correct FtsZ concentration, are required for division to occur at normal cell sizes. After a transient division delay during the transition to lower IPTG concentrations, cells in which ftsZ is expressed continuously (yielding 80% of the wild-type FtsZ levels) divide with the same division time as the wild type, but at the expense of becoming 1.5 times larger. A precise control of ftsZ expression is required for normal division, but the existence of additional regulators to maintain the correct timing during the cell cycle cannot be ruled out.

[Study of prevalence of pain at the Juan Canalejo Hospital in La Coruña]

A study of prevalence of pain conducted in 812 patients admitted in the Juan Canalejo Hospital in La Coruña (Spain). This is primarily an adult hospital. Of the 650 patients whose replies were deemed valid, 35.69% were suffering pain. Other findings were that the sociocultural level of the patients affected their assessment of pain and that 46.12% of those who were suffering pain were not receiving analgesics at that time. Magnesium dipyrone, a combination of paracetamol and codeine and morphine were the most commonly used drugs, although there was clearunderuse of analgesic.

Transcription of ftsZ oscillates during the cell cycle of Escherichia coli

The FtsZ protein is a key element controlling cell division in Escherichia coli. A powerful transcription titration assay was used to quantify the ftsZ mRNA present in synchronously dividing cells. The ftsZ mRNA levels oscillate during the cell cycle reaching a maximum at about the time DNA replication initiates. This cell cycle dependency is specifically due to the two proximal ftsZ promoters. A strain was constructed in which expression of ftsZ could be modulated by an exogenous inducer. In this strain cell size and cell division frequency were sensitive to the cellular FtsZ contents, demonstrating the rate-limiting role of this protein in cell division. Transcriptional activity of the ftsZ promoters was found to be independent of DnaA, indicating that DNA replication and cell division may be independently controlled at the time when new rounds of DNA replication are initiated. This suggests a parallelism between the prokaryotic cell cycle signals and the START point of eukaryotic cell cycles.

Total and lipid-bound serum sialic acid as markers for carcinoma of the uterine cervix

Concentrations of total sialic acid (TSA) and lipid-bound sialic acid (LSA) were determined in serum samples from 88 patients with squamous cell carcinoma of the cervix, 26 normal subjects, and 44 patients with benign uterine or ovarian disease. TSA concentrations in patients with cervical cancer were found to correlate with advanced-stage disease. LSA concentrations were only increased in stage IV of the disease. Sensitivity of the test for stage IB was zero for TSA and 27% for LSA. The specificity of both markers was about 80% due to a low incidence of false-positive values in the pathologic control group. Measurements of TSA or LSA appear to be of no value for the early detection of cervical cancer or to complement the clinical staging of this tumor.

An amino-proximal domain required for the localization of FtsQ in the cytoplasmic membrane, and for its biological function in Escherichia coli

The location of FtsQ, an Escherichia coli protein essential for cell division, is, under physiological conditions, in the cytoplasmic membrane facing towards the periplasmic space. An amino-proximal hydrophobic domain is required for FtsQ to reach its location and for its activity in the cell. Overexpression of modified forms of FtsQ is deleterious for the cell.

Novel solid-phase synthesis of thiol-terminated-poly(alpha-amino acid)-drug conjugate

A new method using a controlled pore glass solid support for the preparation of a thiol-terminated-polymerdrug, notably poly-L-glutamate-daunomycin having a terminal thiol group, is described. The method consists of first polymerizing an ester-protected glutamic acid onto an amino-disulfide functionalized controlled pore glass support. The ester protecting group is then removed, freeing the gamma-carboxyl groups of the grafted polymer which then allows it to react with daunomycin. Finally, the disulfide bond linking the conjugated polymer-drug to the solid support is broken by thiolysis, thus releasing the desired product. The final product consists of only polymer-drug conjugates with terminal thiol groups (global yield 26%). This novel method is much simpler and more elegant than more conventional preparation methods requiring solution phase techniques.

Preferential cytoplasmic location of FtsZ, a protein essential for Escherichia coli septation

An ftsZ thermonull mutant has been constructed in which the ftsZ gene has been deleted from the Escherichia coli chromosome while maintaining a wild-type copy of the gene in a thermosensitive plasmid. Under conditions in which the ftsZ+ allele is unable to be replicated at the same pace as the chromosome, the cells become non-viable and grow as filaments, indicating that, contrary to other reports, FtsZ performs a function essential for cell survival. Antibodies raised against FtsZ have been used to detect the cellular location of FtsZ and its contents per cell. Fractionation experiments indicate that most of the total FtsZ present in the cell stays in the cytoplasm.

On the chronology and topography of bacterial cell division

Gene products that play a role in the formation of cell septum should be expected to be endowed with a set of specific properties. In principle, septal proteins should be located at the cell envelope. The expression of division genes should ensure the synthesis of septal proteins at levels commensurate with the needs of cell division at different rates of cell duplication. We have results indicating that some fts genes located within the 2.5-min cluster in the Escherichia coli chromosome conform to these predictions.

Growth hormone producing pituitary adenomas with concomitant hypersecretion of prolactin are particularly sensitive to photon irradiation

The effect of photon irradiation (50 Gy with a 3-field technique in fractionated doses) on growth hormone (GH), prolactin (PRL), and somatomedin A (SMA) was studied in 25 patients with acromegaly after previous unsuccessful surgery. In patients with concomitant hypersecretion of PRL, the GH reduction was 70 +/- 22% 1 year and 88 +/- 10% 3 years after radiotherapy. The corresponding reductions in patients with isolated GH hypersecretion were 42 +/- 25% and 60 +/- 22%. The reduction of GH levels was most notable the first year after radiotherapy in 16 patients and during the second year in 7 patients. Serum PRL decreased after radiotherapy in all patients with hyperprolactinemia, whereas PRL in normoprolactinemic patients showed inconsistent changes, including PRL increments in 8/12 patients. The effect of radiotherapy on GH and PRL was not correlated to the irradiation target volume or the cumulative radiation effect. SMA levels decreased after radiotherapy, but became normal only in 3 patients, all with pretreatment GH less than 5 micrograms/l. Radiotherapy, 3 years after treatment, appeared to be equivalent to the primary surgical intervention in reducing GH and SMA in patients with acromegaly due to advanced macroadenomas. Patients with concomitant hyperprolactinemia showed increased sensitivity to radiation compared to normoprolactinemic patients with acromegaly.