siRNA knockdown of mitochondrial thymidine kinase 2 (TK2) sensitizes human tumor cells to gemcitabine

Nucleoside metabolism enzymes are determinants of chemotherapeutic drug activity. The nucleoside salvage enzyme deoxycytidine kinase (dCK) activates gemcitabine (2', 2'-difluoro-2'-deoxycytidine) and is negatively regulated by deoxycytidine triphosphate (dCTP). Reduction of dCTP in tumor cells could, therefore, enhance gemcitabine activity. Mitochondrial thymidine kinase 2 (TK2) phosphorylates deoxycytidine to generate dCTP. We hypothesized that: (1) TK2 modulates human tumor cell sensitivity to gemcitabine, and (2) antisense knockdown of TK2 would decrease dCTP and increase dCK activity and gemcitabine activation. siRNA downregulation of TK2 sensitized MCF7 and HeLa cells (high and moderate TK2) but not A549 cells (low TK2) to gemcitabine. Combined treatment with TK2 siRNA and gemcitabine increased dCK. We also hypothesized that TK2 siRNA-induced drug sensitization results in mitochondrial damage that enhances gemcitabine effectiveness. TK2 siRNA and gemcitabine decreased mitochondrial redox status, DNA content, and activity. This is the first demonstration of a direct role for TK2 in gemcitabine resistance, or any independent role in cancer drug resistance, and further distinguishes TK2 function from that of other dTMP-producing enzymes [cytosolic TK1 and thymidylate synthase (TS)]. siRNA knockdown of TK1 and/or TS did not sensitize cancer cells to gemcitabine indicating that, among the 3 enzymes, only TK2 is a candidate therapeutic target for combination with gemcitabine.

Long-term psychosocial and behavioral adjustment in individuals receiving genetic test results in Lynch syndrome

A cross-sectional study of 155 participants who underwent genetic testing for Lynch syndrome (LS) examined long-term psychosocial and behavioral outcomes. Participants completed standardized measures of perceived risk, psychosocial functioning, knowledge, and a questionnaire of screening activities. Participants were on average 47.3 years and had undergone testing a mean of 5.5 years prior. Eighty four (54%) tested positive for a LS mutation and 71 (46%) negative. For unaffected carriers, perceived lifetime risk of colorectal cancer was 68%, and surprisingly, 40% among those testing negative. Most individuals demonstrated normative levels of psychosocial functioning. However, 25% of those testing negative had moderate depressive symptoms, as measured by the Center for Epidemiologic Studies for Depression Scale, and 31% elevated state anxiety on the State-Trait Anxiety Inventory. Being female and a stronger escape - avoidant coping style were predictive of depressive symptoms. For state anxiety, similar patterns were observed. Quality of life and social support were significantly associated with lower anxiety. Carriers maintained higher knowledge compared to those testing negative, and were more engaged in screening. In summary, most individuals adapt to genetic test results over the long term and continue to engage in screening. A subgroup, including some non-carriers, may require added psychosocial support.

Development and validation of an instrument to measure the impact of genetic testing on self-concept in Lynch syndrome

A positive genetic test result may impact on a person's self-concept and affect quality of life. The purpose of the study was to develop a self-concept scale to measure such impact for individuals carrying mutations for a heritable colorectal cancer Lynch syndrome (LS). Two distinct phases were involved: Phase 1 generated specific colorectal self-concept candidate scale items from interviews with eight LS carriers and five genetic counselors, which were added to a previously developed self-concept scale for BRCA1/2 mutation carriers, Phase II had 115 LS carriers complete the candidate scale and a battery of validating measures. A 20-item scale was developed with two dimensions identified through factor analysis: stigma/vulnerability and bowel symptom-related anxiety. The scale showed excellent reliability (Cronbach's α = 0.93), good convergent validity by a high correlation with impact of event scale (r(102) = 0.55, p < 0.001) and Rosenberg self-esteem scale (r(108) = -0.59, p < 0.001), and a low correlation with the Fear questionnaire (r(108) = 0.37, p < 0.001). The scale's performance was stable across participant characteristics. This new scale for measuring self-concept has potential to be used as a clinical tool and as a measure for future studies.

Just because we can, should we? A discussion of treatment withdrawal

Children's nurses are vocationally committed to promoting the health of children, relieving their suffering, enhancing their development, helping them to achieve a sense of worth and a confidence in their future. Supporting parents and medical colleagues while the decision is made to withdraw or withhold life-sustaining treatment is one of the most difficult aspects of children's nursing practice. Current guidelines support the withholding or withdrawing of life-sustaining treatment from children in brain death, permanent vegetative state, and no chance, no purpose or unbearable situations. Societal and professional attitudes to euthanasia and assisted suicide may be changing and this could lead to changes in legislation and guidelines. However, nurses must be clear about the differences: currently any measure, practice or treatment administered with the primary intention to cause death is not allowed. This is not the same as any measure, practice or treatment administered with the intent to relieve suffering and promote comfort, that can cause or hasten death.

Perioperative fluid therapy in children: a survey of current prescribing practice †

BACKGROUND

Fluid therapy in children may be associated with iatrogenic hyponatraemia. We surveyed anaesthetists' current fluid prescribing practice during the perioperative period, departmental fluid protocols and awareness of the concerns of the Royal College of Paediatrics and Child Health (RCPCH) about the use of dextrose 4%/saline 0.18% in children.

METHODS

Questionnaire survey of 477 consultant anaesthetists in two training areas in the UK.

RESULTS

Responses were received from 289 anaesthetists (60.6%)--responses from the 203 consultants that anaesthetized children were analysed. A total of 67.7% did not have a local departmental policy for fluid prescription, and 58.1% were unaware of the concerns of RCPCH. A total of 60.1% of anaesthetists said that they prescribed hypotonic dextrose saline solutions in the intraoperative period and 75.2% did so in the postoperative period. Anaesthetists working in specialist paediatric hospitals were 5.1 times more likely to prescribe isotonic fluids intraoperatively than those working in district hospitals (95% CI 1.48-17.65, P=0.01), but they all prescribed hypotonic dextrose saline solutions postoperatively. The Holliday and Segar formula for maintenance fluid was quoted by 81.8% of anaesthetists; only 5.9% of anaesthetists would restrict fluids in the immediate postoperative period. Anaesthetists working in specialist paediatric hospitals were 13.2 times more likely to restrict fluids postoperatively than those working in district hospitals (95% CI 2.8-61.8, P=0.001).

CONCLUSIONS

The prescription of hypotonic dextrose saline solutions by anaesthetists may be putting children at risk from iatrogenic hyponatraemia. Departmental protocols for perioperative fluid prescription in children are uncommon. We suggest that national guidance is required.

Neuroprotection after spinal cord injury: state of the science

Advances in the basic and clinical sciences are improving our ability to alter the course of injury that occurs after acute spinal cord trauma. Methylprednisolone, naloxone, GM-1 ganglioside, tirilazad mesylate and other agents have been or are currently being subjected to rigorous testing to determine their ability to protect compromised but viable cellular elements and improve the functional outcome of survivors. The authors summarize mechanisms of secondary (spinal cord) injury, discuss derivative pharmacotherapy, review clinical trial findings and raise issues related to future research. Special attention is directed to the Maryland studies of GM-1 ganglioside and the National Acute Spinal Cord Injury trials. Preliminary work regarding the roles of excitatory amino acids, endogenous opioid peptides, calcium channel blockers and nerve growth factors in secondary injury are also outlined.

Precision and accuracy of clinical and radiological signs in premature infants at risk of patent ductus arteriosus

OBJECTIVE

To determine the precision (interobserver agreement) and accuracy (agreement with criterion standard) of clinical and radiological signs in premature infants at risk of patent ductus arteriosus (PDA) with left-to-right shunting.

DESIGN

Masked comparison of clinical and radiological examination with Doppler flow echocardiography (criterion standard).

SETTING

Neonatal intensive care unit.

PATIENTS

One hundred infants with birth weights less than 1750 g were studied once between days 3 and 7 of life. A third of the cohort was intubated at the time of study.

INTERVENTION

Five independent observers noted the presence or absence of an increased pulse volume, an active precordium, a heart murmur, a cardiothoracic ratio greater than 60%, increased pulmonary vascular markings on a concurrent chest x-ray film, and a relative increase of the cardiothoracic ratio compared with that from the previous chest x-ray film. Pulsed and color flow Doppler echocardiography was performed within 4 hours. All 100 tapes were reviewed by a second pediatric cardiologist.

RESULTS

Twenty-three infants had a PDA with left-to-right shunting. The precision of clinical signs was modest, with average kappa values of 0.15 for pulse volume, 0.32 for precordium, and 0.41 for murmur. Pulse quality (43%) and murmur (42%) had the highest mean sensitivities. Corresponding specificities were 74% for pulse volume and 87% for murmur. The combination of a cardiac murmur with an abnormal pulse volume had the highest positive predictive value (77%). The radiological examination did not improve the observers' ability to distinguish between patients with and without PDA.

CONCLUSIONS

The precision and accuracy of clinical and radiological signs of a PDA with left-to-right shunting are unsatisfactory. Therefore, Doppler flow echocardiography is required to diagnose PDA confidently in preterm infants between days 3 and 7 of life.

Development and preliminary testing of the neurological assessment instrument

The purpose of this study was to test a neurological assessment instrument (NAI), used to assess neurological function in adults with acute brain lesions. Instrument items were designed to reflect different aspects of neurological function and assess consciousness along the arousal/awareness continuum as described by Plum and Posner. Content of the NAI was validated by 10 neuroscience expert physicians, nurses and speech pathologists. Reliability was tested with one pair of raters on 39 neurologically stable patients with acute brain lesions. Based on preliminary findings, the critical preliminary steps have been taken towards establishing a reliable and valid instrument with the potential of improving the assessment of neurological function in patients with acute brain lesions.

Parental stress in paediatric intensive care

Family-centred care has become an important concept in paediatric nursing. However, there are factors within the paediatric intensive care environment that act as barriers to implementing family-centred care and maintaining the caring relationship between the parents and their critically ill child.

Methylprednisolone after spinal cord injury

The assumption that maximal spinal cord injury occurs at the moment of trauma is being challenged by emerging evidence that cellular injury continues after the acute event. Efforts are now being made to alter the course of secondary injury in order to improve the functional outcome of survivors. Methylprednisolone has been studied in two clinical trials--the National Acute Spinal Cord Injury Studies (NASCIS I, NASCIS II)--to determine its ability to protect compromised but viable cellular elements, and thus improve outcome. The purpose of this paper is threefold: (1) to explore the putative mechanisms of secondary spinal cord injury, (2) to examine the role of methylprednisolone in spinal cord injury, and (3) to discuss the findings and clinical implications of NASCIS I and NASCIS II.

The Glasgow Coma Scale: time for change

OBJECTIVE

To summarize and evaluate evidence on the psychometric properties of the Glasgow Coma Scale (GCS).

RESULTS

This instrument attempts to capture the phenomenon of consciousness with three gross indicators of nervous system function. Although the GCS does capture consciousness to a limited extent and has pragmatic utility for practitioners, it suffers serious limitations for clinical monitoring and prediction and is being eclipsed by a variety of other instruments.

CONCLUSION

In spite of its acknowledged shortcomings and the emergence of parallel instruments with greater reliability and validity, the GCS continues to enjoy a privileged, but unwarranted, position in clinical and investigational contexts.

The English special hospital--a 12-17 year follow-up study: a comparison of violent and non-violent re-offenders and non-offenders

As part of a more general follow-up study of men admitted to English special hospitals during the period 1961–65 and who left the hospitals before 1 January 1978, comparisons were made between those who subsequently were convicted of violent offences, those who offended non-violently, and those who did not offend at all. Pre-admission and post-discharge behaviour was examined and differences were found to exist between all three groups on a number of variables.

Trial of low doses of aspirin as prophylaxis in sickle cell disease

The effects of low doses of aspirin on the frequency and severity of painful vaso-occlusive crises were evaluated in children with sickle hemoglobinopathies. Aspirin was compared with placebo in 49 patients in a double-blind crossover study. Careful monitoring of patients revealed an average of 1.1 painful crises per patient year. During the 21 months of study, 70% of patients had a maximum of two painful crises, and 25% experienced four or more. The frequency and severity of crises were not affected by aspirin therapy. In view of aspirin's demonstrated effect on platelet function, we suggest that platelets do not contribute to the initiation or progression of the vaso-occlusive process.

Behavioural types of rape

The previous and subsequent convictions of all those charged with rape in 1961 were studied, together with circumstances of the criminal offence. The proportion of victims whose names were published in newspapers was high (26 per cent) and a high proportion of accused were acquitted (22 per cent). They fell fairly obviously into paedophiliac rapes of girls under 14 (30 per cent), "aggressive" rapists (20 per cent) with a record of other aggressive offences, and "others" (50 per cent) with few if any other convictions. Various aspects of the records of these groups are considered. The paedophiles tended to have a wider age range and more often pleaded or were found guilty, and more of them received a medical disposal, rare in others. A small but similar proportion of acquitted and convicted were subsequently convicted of another rape.