Induction of cyclophosphamide-resistance by aldehyde-dehydrogenase gene transfer

The identification of genes inducing resistance to anticancer chemotherapeutic agents and their introduction into hematopoietic cells represents a promising approach to overcome bone marrow toxicity, the limiting factor for most high-dose chemotherapy regimens. Because resistance to cyclophosphamide has been correlated with increased levels of expression of the aldehyde-dehydrogenase (ALDH1) gene in tumor cell lines in vitro, we tested whether ALDH1 overexpression could directly induce cyclophosphamide resistance. We have cloned a full- length human ALDH1 cDNA and used retroviral vectors to transduce it into human (U937) and murine (L1210) hematopoietic cell lines that were then tested for resistance to maphosphamide, an active analogue of cyclophosphamide. Overexpression of the ALDH1 gene resulted in a significant increases in cyclophosphamide resistance in transduced L1210 and U937 cells (50% inhibition concentration [IC50], approximately 13 mumol/L). The resistant phenotype was specifically caused by ALDH1 overexpression as shown by its reversion by disulfiram, a specific ALDH1 inhibitor. ALDH1 transduction into peripheral blood human hematopoietic progenitor cells also led to significant increases (4- to 10-fold; IC50, approximately 3 to 4 mumol/L) in cyclophosphamide resistance in an in vitro colony-forming assay. These findings indicate that ALDH1 overexpression is sufficient to induce cyclophosphamide resistance in vitro and provide a basis for testing the efficacy of ALDH1 gene transduction to protect bone marrow cells from high-dose cyclophosphamide in vivo.     

Colorectal cancer and pollution

The incidence of colorectal carcinoma is increasing in young patients, in contrast to the well established wisdom that it is exclusively diagnosed in patients older than 40 years. In this survey, we examined all possible risk factors, and we recommend a number of measures for early detection in young patients who are at risk of developing this malignant tumor.     

Is the DHEAS/cortisol ratio a potential filter for non-operable constipated cases?

Constipation is a significant manifestation of a number of psychological disorders.Published papers recommend using self-assessment questionnaires for discriminating psychological from non-psychological constipated patients before operating on them but reports from major surveys revealed that general practitioners failed to diagnose 70%of depressed patients using self-assessment questionnaires.Lower circulating concentrations of progesterone,17-hydroxyprogesterone,cortisol,testosterone,androstenedione,and d...     

Chromosome imbalances in syndromic hearing loss

The cause of hearing impairment has not been elucidated in a large proportion of patients. We screened by 1-Mb array-based comparative genomic hybridization (aCGH) 29 individuals with syndromic hearing impairment whose clinical features were not typical of known disorders. Rare chromosomal copy number changes were detected in eight patients, four de novo imbalances and four inherited from a normal parent. The de novo alterations define candidate chromosome segments likely to harbor dosage-sensitive genes related to hearing impairment, namely 1q23.3–q25.2, 2q22q23, 6p25.3 and 11q13.2–q13.4. The rare imbalances also present in normal parents might be casually associated with hearing impairment, but its role as a predisposition gene remains a possibility. Our results show that syndromic deafness is frequently associated with chromosome microimbalances (14–27%), and the use of aCGH for defining disease etiology is recommended.     

Changes in General Nurses' Knowledge of Alcohol and Substance Use and Misuse After Education

PURPOSE.  This study aims to assess the impact of an education program on Australian general nurses' knowledge and competence in identifying and managing patients with alcohol and substance use and misuse, and compare findings with existing literature on mental health nurses.
DESIGN AND METHODS.  Pre- and posttest design without a control group.
FINDINGS.  The nurses' knowledge of safe drinking limits and alcohol withdrawal management improved following the education. Nevertheless, overall the nurses reported a lack of adequate knowledge and competence. Compared to mental health nurses, the nurses in this study had lower levels of knowledge and competence.
PRACTICE IMPLICATIONS.  We suggest several opportunities for general nurses to strengthen their knowledge and skills and the need for a comprehensive and regular education program.     

In vitro and in vivo pharmacological role of TLQP-21, a VGF-derived peptide,in the regulation of rat gastric motor functions

Background and purpose:

Vgf gene expression has been detected in various endocrine and neuronal cells in the gastrointestinal tract. In this study we investigated the pharmacological activity of different VGF-derived peptides. Among these, TLQP-21, corresponding to the 556–576 fragment of the protein was the unique active peptide, and its pharmacological profile was further studied.

Experimental approach:

The effects of TLQP-21 were examined in vitro by smooth muscle contraction in isolated preparations from the rat gastrointestinal tract and, in vivo, by assessing gastric emptying in rats. Rat stomach tissues were also processed for immunohistochemical and biochemical characterization.

Key results:

In rat longitudinal forestomach strips, TLQP-21 (100 nmol·L⁻¹–10 µmol·L⁻¹) concentration-dependently induced muscle contraction (in female rats, EC₅₀ = 0.47 µmol·L⁻¹, E_max: 85.7 ± 7.9 and in male rats, 0.87 µmol·L⁻¹, E_max: 33.4 ± 5.3; n = 8), by release of prostaglandin (PG)E₂ and PGF_2a from the mucosal layer. This effect was significantly antagonized by indomethacin and selective inhibitors of either cyclooxygenase-1 (S560) or cyclooxygenase-2 (NS398). Immunostaining and biochemical studies confirmed the presence of VGF in the gastric neuronal cells. TLQP-21, injected i.c.v. (2–32 nmol per rat), significantly decreased gastric emptying by about 40%. This effect was significantly (P < 0.05) blocked by i.c.v. injection of indomethacin, suggesting that, also in vivo, this peptide acts in the brain stimulating PG release.

Conclusions and implications:

The present results demonstrate that this VGF-derived peptide plays a central and local role in the regulation of rat gastric motor functions.     

Experience as a doctor in the developing world: does it benefit the clinical and organisational performance in general practice?

Background

Lipid-lowering medication remains underused, even in high-risk populations. The objective of this study was to determine factors underlying general practitioners' decisions not to prescribe such drugs to patients with type 2 diabetes.

Methods

A qualitative study with semi-structured interviews using real cases was conducted to explore reasons for not prescribing lipid-lowering medication after a guideline was distributed that recommended the use of statins in most patients with type 2 diabetes. Seven interviews were conducted with general practitioners (GPs) in The Netherlands, and analysed using an analytic inductive approach.

Results

Reasons for not-prescribing could be divided into patient and physician-attributed factors. According to the GPs, some patients do not follow-up on agreed medication and others object to taking lipid-lowering medication, partly for legitimate reasons such as expected or perceived side effects. Furthermore, the GPs themselves perceived reservations for prescribing lipid-lowering medication in patients with short life expectancy, expected compliance problems or near goal lipid levels. GPs sometimes postponed the start of treatment because of other priorities. Finally, barriers were seen in the GPs' practice organisation, and at the primary-secondary care interface.

Conclusion

Some of the barriers mentioned by GPs seem to be valid reasons, showing that guideline non-adherence can be quite rational. On the other hand, treatment quality could improve by addressing issues, such as lack of knowledge or motivation of both the patient and the GP. More structured management in general practice may also lead to better treatment.