Advances and Challenges of Endoscopic Spine Surgery

The purpose of this paper is to review the data supporting current endoscopic surgical techniques for the spine and the potential challenges and future of the field. The origins of endoscopic spine surgery can be traced back many decades, with many important innovations throughout its development. It can be applied to all levels of the spine, with many robust trials supporting its clinical outcomes. Continued clinical research is needed to explore its expanding indications. Although the limitations of starting an endoscopic program can be justified by its cost effectiveness and positive societal impact, challenges facing its widespread adoption are still present. As more residency and fellowship programs include endoscopy as part of their spine training, it will become more prevalent in hospitals in the United States. Technological advancements in spine surgery will further propel and enhance endoscopic techniques as they become an integral part of a spine surgeon's repertoire.

Ptychographic amplitude and phase reconstruction of bichromatic vortex beams

We experimentally demonstrate that ptychographic coherent diffractive imaging can be used to simultaneously characterize the amplitude and phase of bichromatic orbital angular momenta-shaped vortex beams, which consist of a fundamental field, together with its copropagating second-harmonic field. In contrast to most other orbital angular momentum characterization methods, this approach solves for the complex field of a hyperspectral beam. This technique can also be used to characterize other phase-structured illumination beams, and, in the future, will be able to be extended to other complex fields in the extreme ultraviolet or X-ray spectral regions, as well as to matter waves.

Spine and Spinal Cord Injuries After Falls From Tree Stands During the Wisconsin Deer Hunting Season

BACKGROUND

Deer hunting is popular in much of the United States. In Wisconsin, use of tree stands for hunting is common. Spine surgeons at a Level 1 Trauma Center observed a high incidence of spine and spinal cord injury due to falls from tree stands while hunting. This study's purpose is to systematically characterize and classify those injuries.

METHODS

We reviewed the University of Wisconsin Hospital and Clinics' trauma database for tree stand-related injuries from 1999 to 2013. We collected and analyzed data pertaining to hunters' demographics, comorbidities, type and mechanism of injury, injury severity, and management.

RESULTS

We identified 117 patients evaluated after a tree stand fall. Sixty-five (ages 16-76) suffered spine fractures that occurred at all levels, from occipital condyle to sacrum, with thoracolumbar compression and burst fractures being most common. Fractures occurred in the following locations: cranio-cervical junction (8.7%), cervical spine (7.6%), cervical-thoracic junction (6.5%), thoracic spine (32.6%), thoracolumbar junction (33.7%), and lumbar spine (10.9%). Twenty-one patients (32%) experienced a single spinal fracture; 44 patients (68%) suffered multiple spinal fractures. Twenty-five patients (38%) required surgical fixation; 19 patients experienced loss of neurologic function: 5 complete spinal cord injuries (SCI), 5 incomplete SCI, 2 central cord syndromes, and 8 radiculopathies. Two mortalities, both of cardiopulmonary etiology, were noted-one in a patient without a spine fracture and the other in a patient with a complete spinal cord injury at T4.

CONCLUSIONS

The majority of spine fractures are treated nonoperatively. However, enough patients require surgical intervention that consultation with a neurosurgical or orthopedic spine surgeon is prudent. It is more common to have multiple spine fractures from a tree stand fall, therefore, it is recommended that if 1 fracture is identified the entire spine be evaluated for additional fractures. For safety, it is recommended that hunters wear and use safety harnesses appropriately. Additionally, keeping the height of the tree stand at 10 feet or less is associated with a lower likelihood of spinal cord injury. Further study is needed to determine additional interventions such as education that might reduce the injury frequency in this population.

Microfluidic generation of droplet interface bilayer networks incorporating real-time size sorting in linear and non-linear configurations

In this study, a novel droplet based microfluidic method for the generation of different sized droplet interface bilayers is reported. A microfluidic platform was designed, which allows the generation and packing of picoliter lipid coated water droplets. Droplets were generated by hydrodynamic focusing coupled with selective transport along grooves according to their size. A trapping structure at the end of the groove and a fine control of the flow pressures allowed for the droplets to be successfully trapped and aligned on demand. This technology facilitates the fine control of droplet size production as well as the generation of extended networks from a variety of lipids including 1,2-diphytanoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine in linear and non-linear configurations, which is vital to the application of Droplet Interface Bilayers to biological network construction on-chip.

A red palm oil diet can reduce the effects of oxidative stress on rat spermatozoa

Male Wistar rats (n = 54) received daily supplementation of red palm oil (RPO: 0, 2, 4 ml). Subgroups were subsequently injected with saline, cumene hydroperoxide (cHP, 10 μm) or t-butyl hydroperoxide (tbHP, 20 μm) over a 60-day period after which animals were sacrificed. Epididymal sperm motility, concentration, reactive oxygen species (ROS), lipid peroxidation and enzymes were measured. Sperm concentration, motility, superoxide dismutase (SOD) concentration, glutathione (GSH) and catalase (CAT) activities were significantly lower, while dichlorofluorescein (DCF) and malondialdehyde (MDA) were higher in sperm of hydroperoxide-treated animals compared to controls (P < 0.05). DCF and MDA levels were significantly lower, while SOD, CAT and GSH were significantly higher in the sperm of rats supplemented with RPO in combination with hydroperoxide treatment when compared to those receiving hydroperoxide and no RPO supplementation (P < 0.05). Moreover, the DCF, SOD, CAT and GSH levels in the RPO hydroperoxide groups did not differ from control values (P > 0.05). RPO supplementation can successfully attenuate the oxidative stress-induced sperm damage due to organic hydroperoxide exposure. We therefore propose that a daily intake of RPO supplement to the diet might be helpful in protecting males against the adverse effects of high ROS in sperm function and help preserve fertility.

PPARgamma agonist rosiglitazone is neuroprotective after traumatic brain injury via anti-inflammatory and anti-oxidative mechanisms

Peroxisome proliferator-activated receptor (PPAR)-gamma is a ligand-activated transcription factor of nuclear hormone receptor superfamily. Thiazolidinedione rosiglitazone is a potent agonist of PPARgamma which was shown to induce neuroprotection in animal models of focal ischemia and spinal cord injury. We currently evaluated the therapeutic potential of rosiglitazone (6 mg/kg at 5 min, 6 h and 24 h; i.p.) following controlled cortical impact (CCI)-induced traumatic brain injury (TBI) in adult mice. CCI injury increased the cortical PPARgamma mRNA levels which were further elevated by rosiglitazone treatment. In addition, rosiglitazone treatment significantly decreased the cortical lesion volume measured at 7 days compared to vehicle treatment (by 56+/-7%; p<0.05; n=6/group). Following TBI, the spared cortex of the rosiglitazone group showed significantly less numbers of GSI-B4(+) activated microglia/macrophages and ICAM1(+) capillaries, and curtailed induction of pro-inflammatory genes IL6, MCP1 and ICAM1 compared to vehicle group. Rosiglitazone-treated mice also showed significantly less number of TUNEL(+) apoptotic neurons and curtailed induction of caspase-3 and Bax, compared to vehicle control. In addition, rosiglitazone significantly enhanced the post-TBI expression of the neuroprotective chaperones HSP27, HSP70 and HSP32/HO1, and the anti-oxidant enzymes catalase, Cu/Zn-SOD and Mn-SOD, compared to vehicle. Treatment with GW9662 (a specific PPARgamma antagonist) prevented all the above PPARgamma-mediated actions. Thus, PPARgamma activation confers neuroprotection after TBI by anti-inflammatory, anti-apoptotic and anti-oxidative mechanisms.

Transcription factor early growth response-1 induction mediates inflammatory gene expression and brain damage following transient focal ischemia

Early growth response-1 (Egr1) is a sequence-specific transcription factor (TF) which is induced under hypoxic conditions. We presently report that transient middle cerebral artery occlusion (MCAO) leads to increased expression of Egr1 in the brains of adult mice and rats between 2 h and 5 days of reperfusion with a peak increase of 8-12-fold at 1 day. When subjected to transient MCAO and 3 days of reperfusion, Egr1-/- mice showed significantly smaller infarcts (by 44.9 +/- 8.4%, p < 0.05) and improved neurological function than Egr1+/+ littermates. Following transient MCAO, brains of Egr1-/- mice showed less water accumulation and decreased neutrophil infiltration (by 42 +/- 8%, p < 0.05) compared to Egr1+/+ mice. The number of activated microglia/macrophages were also significantly lower (OX42+ cells by 53 +/- 9%, p < 0.05 and ED1+ cells by 59 +/- 11%) in the post-ischemic cortex of Egr1-/- mice compared to Egr1+/+ mice. In addition, post-ischemic inflammatory gene expression was less pronounced in the brains of Egr1-/- mice compared to Egr1+/+ mice. Preventing cerebral Egr1 protein induction with small interference RNAs that target Egr1 decreased inflammatory gene expression and led to smaller infarcts (by 40.2 +/- 6.9%, p < 0.05) and reduced neurological deficits in rats subjected to transient MCAO. Conversely, transient MCAO following adenoviral-mediated Egr1 over-expression exacerbated the infarct volume (by 29 +/- 5.3%, p < 0.05) and worsened the neurological deficits in rats. These studies indicate Egr1 as a significant contributor of inflammation and neuronal damage after stroke.

Utilization of self-expanding stents in the treatment of intracranial atherosclerotic disease in the distal small cerebral vessels

INTRODUCTION

Previously, endovascular treatment of stenosis related to intracranial atherosclerosis (ICAD) involving arteries measuring less than 2 mm in diameter was limited. To our knowledge, there are no reports in the literature addressing stent placement for treatment of stenosis in arteries of this size.

METHODS

Four patients aged 33 to 80 years (mean 57.5 years) with medically refractory ICAD underwent angioplasty and stenting of small (<2 mm) distal intracerebral arteries. Vessel location and length of follow-up were anterior cerebral artery (ACA) A1 segment (5 months), ACA A2 segment (18 months), middle cerebral artery M1 segment (18 months), and posterior cerebral artery P1 segment (8 months) with vessel calibers ranging from 1.2 to 1.8 mm. Clinical and imaging follow-up ranged from 5 to 18 months.

RESULTS

All procedures were successfully performed without complications. Follow-up out to 18 months demonstrated one vessel that went on to occlusion while the other stented vessel segments remained patent. One patient died 8 months after stenting, but the death was not related to neurological disease. The remaining patients experienced resolution of the presenting symptomatology and remained asymptomatic throughout follow-up.

CONCLUSION

In this small series, stenoses of distal (<2 mm) cerebral arteries were amenable to treatment using new self-expanding stents. We safely and successfully treated four arteries smaller than 2 mm in diameter with newer self-expanding stents. All patients remained clinically asymptomatic. One stent occluded at 5 months and the others remained patent during follow-up. Longer term clinical follow-up is required to determine the durability and viability of this therapy.

Treatment of non-cardiac chest pain: a controlled trial of hypnotherapy

BACKGROUND

Non-cardiac chest pain (NCCP) is an extremely debilitating condition of uncertain origin which is difficult to treat and consequently has a high psychological morbidity. Hypnotherapy has been shown to be effective in related conditions such as irritable bowel syndrome where its beneficial effects are long lasting.

AIMS

This study aimed to assess the efficacy of hypnotherapy in a selected group of patients with angina-like chest pain in whom coronary angiography was normal and oesophageal reflux was not contributory.

PATIENTS AND METHODS

Twenty eight patients fulfilling the entry criteria were randomised to receive, after a four week baseline period, either 12 sessions of hypnotherapy or supportive therapy plus placebo medication over a 17 week period. The primary outcome measure was global assessment of chest pain improvement. Secondary variables were a change in scores for quality of life, pain severity, pain frequency, anxiety, and depression, as well as any alteration in the use of medication.

RESULTS

Twelve of 15 (80%) hypnotherapy patients compared with three of 13 (23%) controls experienced a global improvement in pain (p = 0.008) which was associated with a significantly greater reduction in pain intensity (p = 0.046) although not frequency. Hypnotherapy also resulted in a significantly greater improvement in overall well being in addition to a reduction in medication usage. There were no differences favouring hypnotherapy with respect to anxiety or depression scores.

CONCLUSION

Hypnotherapy appears to have use in this highly selected group of NCCP patients and warrants further assessment in the broader context of this disorder.

Complications of diagnostic cardiac catheterisation: results from a confidential inquiry into cardiac catheter complications

OBJECTIVES

To estimate the frequency and nature of complications in patients undergoing diagnostic cardiac catheterisation and to assess time trends in complications since the introduction of a voluntary cooperative audit.

METHODS

Cardiac centres undertaking diagnostic cardiac catheterisation in England and Wales during the 10 years 1990-9 were invited to join the study. Each participating centre reported numbers of patients catheterised each month and details of complications and deaths as they occurred. Complication rates were calculated for the main diagnostic procedures and for each participating hospital and time trends in complications were examined.

RESULTS

41 cardiac centres contributed. 211 645 diagnostic procedures in adults and 7582 paediatric procedures were registered. The majority (87%) of diagnostic catheter studies in adults were left heart studies with coronary arteriography. The overall complication rate for adult procedures was 7.4/1000, with mortality at 0.7/1000; for paediatric procedures the complication rate was similar but mortality rather higher. Complication rates varied between centres but there was little association with caseload. Time trends across the decade showed both complication and mortality decreasing; from 9.5 to 5.8/1000 and from 1.4 to 0.4/1000, respectively.

CONCLUSION

Complication rates of diagnostic catheterisation are low but neither negligible nor irreducible. While voluntary audit of cardiac catheter complications is useful and inexpensive, there is a clear need to establish a formal reporting system in all cardiac catheter laboratories, with clear definitions of reportable complications.

Global iron connections between desert dust, ocean biogeochemistry, and climate

The environmental conditions of Earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. This is the "Earth system": a highly complex entity characterized by multiple nonlinear responses and thresholds, with linkages between disparate components. One important part of this system is the iron cycle, in which iron-containing soil dust is transported from land through the atmosphere to the oceans, affecting ocean biogeochemistry and hence having feedback effects on climate and dust production. Here we review the key components of this cycle, identifying critical uncertainties and priorities for future research.

Endoscopic and minimally invasive microsurgical approaches for treating brain tumor patients

Recent developments in neuroendoscopy and minimally invasive procedures have greatly impacted the diagnosis and treatment of brain tumors. In this paper, we will review these innovations and discuss how they have influenced our approach to the treatment of intraventricular and pituitary tumors. Finally, the concept of keyhole neurosurgery is illustrated by discussing 'eyebrow orbitotomy' approach as an example. As noninvasive therapeutic alternative become available, future neurosurgeons will be challenged to develop effective and less invasive surgical approaches for the diagnosis and treatment of patients will brain tumors.

Quality of life in patients with traumatic brain injury-basic issues, assessment and recommendations

INTRODUCTION

Traumatic brain injuries (TBI) are one of the most common consequences of traffic accidents. Patients with mild, moderate or severe brain injuries suffer from physical, cognitive, behavioral, emotional and social problems. Most of these problems have been a long standing focus amongst practitioners and researchers. Only recently a development has started that took interest in the quality of life outcome of TBI patients. The international members of this consensus meeting reviewed the literature on Quality of Life assessment after TBI and discussed the applicability of different measurements to this specific patient group.

TIME POINTS

During the acute phase (T1; < 3 month after trauma) QoL it is difficult to assess due to the reduced consciousness of TBI patients. In the phase of rehabilitation (T2; < one year after trauma) and in the post-rehabilitation phase (T3) repeated assessment of QoL is recommended.

INSTRUMENTS

Several generic and disease-specific instruments possibly relevant to TBI patients or specifically developed for this group were assessed according to the existing evidence in the literature. Criteria for the evaluation of these instruments were: feasibility, specificity, validity, comprehensiveness, international availability, existence of norms, and psychometric quality. The cognitive impairment and the existential dimension were not sufficiently considered in most of the reviewed instruments.

GROUP CONSENSUS

The family's and relatives' view of the patient's QoL should not be used as a proxy but provides an additional source of information in the acute phase. At T2 and T3, assessment of the patient's quality of life should include a generic as well as a disease specific instrument. Among the generic instruments the SF-36, the EuroQol and the WHO-QoL should be considered. The literature about specific instruments for patients with TBI like the EBIC is scarce. Therefore, the group could hardly give an empirically based recommendation. The need for further investigation on QoL instruments in TBI patients is strongly emphasized.

Care home versus hospital and own home environments for rehabilitation of older people

BACKGROUND

Rehabilitation for older people has acquired an increasingly important profile for both policy-makers and service providers within health and social care agencies. This growing demand for rehabilitation services has generated an increased interest in the use of alternative care environments, for example care home environments, for older persons' rehabilitation. At a time when there is pressure for policy decision-makers and service providers to explore the use of such care settings for the provision of rehabilitation for older people, there appears limited evidence on which to base decisions.

OBJECTIVES

The objective of this review is to compare the effects of care home environments (e.g. nursing home, residential care home and nursing facilities) versus hospital environments and own home environments in the rehabilitation of older people.

SEARCH STRATEGY

The following databases were searched. The Cochrane Effective Practice and Organisation of Care Specialised Register, the Cochrane Rehabilitation Specialist Register; Cochrane Controlled Trials Register (CCTR); MEDLINE (1966-2000); EMBASE (1980-2000), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982-2000): Science Citation Index (1982-2000); Social Science Citation Index (1982-2000); Best Evidence (1991-2000); HMIC (1979-2000); PsycINFO(1967-2000); ASSIA (1987-2000); Ageline (1978-2000); AgeInfo (1971-2000); Sociological Abstracts (1963-2000); System for Information on Grey Literature (SIGLE) (1980-2000); UK National Research Registers Project Database( Issue 1 2001); Architecture Publication Index (1977-2000). The following Journals were hand searched: Disability and Rehabilitation (1992-2000); Disability and Society (1986-2000); Archives of Physical Medicine and Rehabilitation (1985-2000); Journal of the American Geriatric Society (1980-2000); International Journal of Rehabilitation Research (1980-2000); American Journal of Physical Medicine and Rehabilitation (1980-2000) and: Clinical Rehabilitation (1992-2000). The reviewers also consulted subject area experts and obtained full text review articles and forward tracked any references from these sources.

SELECTION CRITERIA

Randomised controlled trials (RCTs), controlled clinical trials (CCTs), controlled before and after studies (CBAs) and interrupted time series (ITS) that compared rehabilitation outcomes for persons 60 years or older who received rehabilitation whilst residing in a care home with those for persons 60 years or older who received rehabilitation in hospital or own home environments. Primary outcomes included functional outcomes using activities of daily living measurement (both personal and instrumental). Secondary outcomes included subjective health status; quality of life measures; return to place of usual residency; all cause mortality; adverse effects; readmission to an acute care facility; patient and carer satisfaction; number of days in facility and number of days receiving rehabilitation.

DATA COLLECTION AND ANALYSIS

One reviewer (DW) completed the initial search and identified potential papers for inclusion. Abstracts for these papers were independently scrutinised by two reviewers (DW/MS) to assess their eligibility. Full text versions of potentially eligible papers were independently assessed by two reviewers (DW/MS). Papers that fulfilled the comparison inclusion criteria were then independently scrutinised by all reviewers to assess whether they met EPOC methodological criteria for inclusion.

MAIN RESULTS

The total yield from the initial search strategy was 19,457. A total of 1,247 abstracts were independently scrutinised by two reviewers (DW/MS) to assess their eligibility. Full text papers for 99 studies were obtained to assess if they fulfilled the review's comparison inclusion criteria. This process resulted in 12 papers being assessed further for methodological validity. However, none of these studies met the inclusion criteria.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to compare the effects of care home environments, hospital environments and own home environments on older persons rehabilitation outcomes. Although the authors acknowledge that absence of effect is not no effect. There are three main reasons; the first is that the description and specification of the environment is often not clear; secondly, the components of the rehabilitation system within the given environments are not adequately specified and; thirdly, when the components are clearly specified they demonstrate that the control and intervention sites are not comparable with respect to the methodological criteria specified by Cochrane EPOC group (Cochrane 1998). The combined effect of these factors resulted in the comparability between intervention and control groups being very weak. For example, there were differences in the services provided in the intervention and control arms, due possibly to differences in dominant remuneration systems, nature of the rehabilitation transformation, patient characteristics, skill mix and academic status of the care environment.

The patient's view: the benefits and limitations of nurse prescribing

This study was undertaken in a primary care group to explore nurse prescribing from the patient/client's viewpoint. All prescribing health visitors, district nurses and practice nurses were asked to recruit five patients for whom they had prescribed; 50 patients/clients participated in the study. Identified benefits of nurse prescribing included a more effective use of the nurse's and doctor's time; a quality relationship between the nurse and patient; nurses' awareness of their own professional limitations; their expertise in certain types of care; and their providing timely, convenient, practical and successful treatment. Limitations and the proposed options for change included the training and competency of nurse prescribers and the limitations of the Nurse Prescribers' Formulary. On a local level the study informs nurse prescribers that they are currently meeting the needs of the majority of recipients, and provides evidence of some of the benefits and limitations of nurse prescribing.

Length of stay in community hospitals

AIM

To identify the factors that contribute to variation in length of stay in hospital.

METHOD

After a pilot study, an audit was undertaken in 11 community hospitals in a single trust over an eight-week period. Each ward was audited once. During the audit period 202 patients' records were reviewed, of which 71 were GP admissions and 131 were consultant admissions.

RESULTS

Patients admitted to community hospitals were older, predominantly female, classed as at risk of malnutrition and had a reduced functional capacity. An increased length of stay could also be due to limited evidence of discharge planning on transfer from acute or residential homes, a lack of information about patients' social circumstances and how the discharge process was progressed, delay from referral to assessment by the multidisciplinary team, and pressure ulcers on admission to hospital.

CONCLUSION

Recommendations for practice are: improved documentation, including an integrated discharge care pathway that is transferable across health and social care; multidisciplinary records; clinical leadership; adapting the current audit tool; and undertaking another audit after the recommendations have been implemented.

Nurse prescribing: what do patients think?

AIM

To explore nurse prescribing from the patient's viewpoint.

METHOD

This study was undertaken in one primary care group in Leicestershire. All prescribing health visitors (n = 17), district nurses (n = 9) and practice nurses (n = 1) were asked to recruit five patients for whom they had prescribed. Fifty patients took part in a telephone or face-to-face interview. Participants were predominantly low or new users of nurse prescribing, while the nurse prescribers were experienced.

RESULTS

Participants identified that nurse prescribers had key skills in assessment, observation, diagnosing and providing information. Nurse prescribing was accepted by all participants as a practical and responsive method of service delivery. Gains identified were better use of the nurse's and doctor's time, convenience, a quality relationship with the nurse and expertise of the nurse. Disadvantages identified included the limitations of the Nurse Prescribers' Formulary and the training and competence of nurse prescribers.

CONCLUSION

This study helps affirm that nurse prescribers meet the needs of patients, with positive experiences in terms of the process and outcomes. Future developments suggested by participants appear to reflect government concerns. Such changes include the need to develop and maintain competence to uphold public safety and for the formulary to be expanded. To ensure that the NHS workforce is used more effectively, participants agreed with providing patient-centred services and the renegotiation of traditional roles.

Influence of corticotrophin releasing factor on neuronal cell death in vitro and in vivo

Several studies have demonstrated that antagonists of the corticotrophin releasing factor (CRF) receptor markedly inhibit experimentally induced excitotoxic, ischaemic and traumatic brain injury in the rat, and that CRF expression is elevated in response to experimentally induced stroke or traumatic brain injury. CRF is also induced by the pro-inflammatory cytokine interleukin 1 (IL-1), which participates in various forms of neurodegeneration. The aim of this study was to test the hypothesis that CRF is toxic directly in vivo or in vitro. In primary cultures of rat cortical neurons, exposure to CRF (10 pM-100 nM) for 24 h failed to cause cell death directly, or to modify the neurotoxic effects of N-methyl-D-aspartate (NMDA). Similarly, infusion of CRF (0.3-5 microg) into specific brain regions of the rat did not induce cell death and did not significantly alter the neuronal damage produced by infusion of excitatory amino acids. These data demonstrate that CRF is not directly neurotoxic, and suggest that either CRF mediates neuronal damage by indirect actions (e.g. on the vasculature) and/or that CRF is not the endogenous ligand which contributes to neurodegeneration through activation of CRF receptors.

Clinical guidelines in community hospitals

AIM

The objective of this study was to investigate the attitudes of community hospital staff towards clinical guidelines.

METHOD

Twenty four staff members from 11 hospitals in one community trust were interviewed. The participants, primarily F and G grade nurses, but also some physiotherapists and occupational therapists, were asked about their use of, attitudes to and sources of clinical guidelines.

RESULTS

A simple gap analysis identified that participants were familiar with local clinical guidelines and generally felt positively about them, but had a few reservations. However, they were generally unaware of national guidelines.

CONCLUSION

This study has identified the reality of implementing and raising awareness of clinical guidelines in practice.

Alteration in the choice of DNA repair pathway with increasing sequence selective DNA alkylation in the minor groove

BACKGROUND

Many conventional DNA alkylating anticancer drugs form adducts in the major groove of DNA. These are known to be chiefly repaired by both nucleotide (NER) and base (BER) excision repair in eukaryotic cells. Much less is known about the repair pathways acting on sequence specific minor groove purine adducts, which result from a promising new class of anti-tumour agents.

RESULTS

Benzoic acid mustards (BAMs) tethering 1-3 pyrrole units (compounds 1, 2 and 3) show increasing DNA sequence selectivity for alkylation from BAM and 1, alkylating primarily at guanine-N7 in the major groove, to 3 which is selective for alkylation in the minor groove at purine-N3 in the sequence 5'-TTTTGPu (Pu=guanine or adenine). This increasing sequence selectivity is reflected in increased toxicity in human cells. In the yeast Saccharomyces cerevisiae, the repair of untargeted DNA adducts produced by BAM, 1 and 2 depends upon both the NER and BER pathways. In contrast, the repair of the sequence specific minor groove adducts of 3 does not involve known BER or NER activities. In addition, neither recombination nor mismatch repair are involved. Two disruptants from the RAD6 mutagenesis defective epistasis group (rad6 and rad18), however, showed increased sensitivity to 3. In particular, the rad18 mutant was over three orders of magnitude more sensitive to 3 compared to its isogenic parent, and 3 was highly mutagenic in the absence of RAD18. Elimination of the sequence specific DNA adducts formed by 3 was observed in the wild type strain, but these lesions persisted in the rad18 mutant.

CONCLUSIONS

We have demonstrated that the repair of DNA adducts produced by the highly sequence specific minor groove alkylating agent 3 involves an error free adduct elimination pathway dependent on the Rad18 protein. This represents the first systematic analysis of the cellular pathways which modulate sensitivity to this new class of DNA sequence specific drugs, and indicates that the enhanced cytotoxicity of certain sequence specific minor groove adducts in DNA is the result of evasion of the common excision repair pathways.

Quality of life and the high-dependency unit

This study was designed to identify and measure the patients' perspective of the concept quality of life within the context of a high-dependency unit (HDU). Data were collected in two phases. In phase one, 55 patients were interviewed, which resulted in the concept clarification of quality of life as: physical, social, psychological and family/friends. In phase two, 51 patients undertook quality-of-life assessment using validated instruments the Quality of Life Index (Ferrans & Powers 1985) and the Global Quality of Life Scale (Hyland & Sodergren 1997). Post-HDU patients demonstrated improvements upon pre-admission scores in both instruments (the social domain in the quality of life index being the exception), although this only reached statistical significance P<0.05 in the overall index score and within the domains of health and family. When exploring variables of age and severity of illness (Apache 2 score, Knaus et al. 1980) it was the people who were older and physiologically compromised to an increased extent (P<0.05) who demonstrated higher levels of satisfaction with their resulting quality of life. This study has been successful in providing patients with an opportunity to participate more actively in service evaluation and has identified the need for future evaluation of HDUs to move beyond physiological measures, to incorporate the impact that illness leading to admission to an HDU has upon the patients' ability to function and their resulting quality of life.

Patients' perspective of quality of care in a high-dependency unit

This study was designed to identify and explore the patients' perspective of the concept quality of care within the context of a high-dependency unit (HDU). Data were collected in two phases. In phase one, 55 patients were interviewed to clarify the concept quality of care. In phase two, 77 patients were interviewed to explore this concept in further detail. This study has clarified the patients' concept of quality of care into the principal constructs of the environment, meeting individual needs, staff attitudes and manners, organization of care, communication, staff skills and family and friends. It has been successful in providing patients with a voice to comment upon an aspect of service provision. A well-known concept has been clarified and applied to a high-dependency environment. This has identified the need for future evaluation of HDUs to go beyond traditional physiological measures, to incorporate the service experience itself and the impact it has upon the patients.

The role of base excision repair in the repair of DNA adducts formed by a series of nitrogen mustard-containing analogues of distamycin of increasing binding site size

The role of base excision repair in the repair of alkylation damage produced by a series of sequence specific oligopyrrole-containing analogues of distamycin A that tether benzoic acid mustard (BAM) has been examined. Whereas BAM alkylates and cross-links in the major groove of DNA, attachment to pyrrole units produces monoalkylations in the minor groove of DNA at AT tracts. Both sequence specificity of alkylation and cytotoxicity increase from one to three attached pyrrole units (compounds 1-3), and with 3 alkylation is selective for purine-N3 in the sequence 5'-TTTTGPu (where Pu = guanine or adenine). In a model bacterial (Escherichia coli) system repair of the sequence specific minor groove alkylations produced by 2 and 3 does not appear to involve BER, since neither a formamidopyrimidine-DNA glycosylase repair deficient E. coli mutant (BH 20, fpg- mutant) nor a 3-methyladenine-DNA glycosylase repair deficient mutant (GC 4803, tag-alkA- mutant) showed increased cytotoxicity to 2 or 3 compared with the wild type, AB 1157. The monopyrrole compound 1 was, however, approximately 4-fold more cytotoxic to the GC 4803 mutant compared with wild type and BH 20, suggesting a role for the 3-methyladenine-DNA glycosylase in the recognition and excision of the adducts formed by 1. In contrast, increased sensitivity (> 10-fold) was observed for the conventional nitrogen mustard BAM in the BH 20 strain, suggesting a role for the formamidopyrimidine-DNA glycosylase in the repair of the lesions produced by the agent. In a cell-free system the E. coli 3-methyladenine-DNA glycosylase (AlkA) was shown to remove alkylations at 5'-TTTTGPu sequences. However, the efficiency in removing the adducts formed by the oligopyrrole compounds decreased dramatically from compound 1 to compound 3. Increasing the size of the DNA adduct formed in the minor groove therefore decreased the efficiency of recognition and removal of the adduct by the DNA glycosylase.

Synthesis, DNA binding, cytotoxicity and sequence specificity of a series of imidazole-containing analogs of the benzoic acid mustard distamycin derivative tallimustine containing an alkylating group at the C-terminus

In an attempt to produce additional alkylation and crosslinking in the minor groove of DNA, imidazole-containing analogs of distamycin were synthesized with benzoic acid mustard (BAM) and methoxyaziridinyl moieties present at the N- and C-termini, respectively. Analogs 1a-c differed in the number of methylene units (2-4 respectively) between the C-terminal carbonyl group and the methoxyaziridinyl moiety. DNA binding affinity to several polynucleotides decreased with increasing linker length, whereas DNA interstrand crosslinking ability, as measured by a plasmid gel based assay, increased. The in vitro cytotoxicity in human chronic myeloid leukemia K562 cells and the panel of human tumor cell lines at the National Cancer Institute decreased with increasing number of methylene units, and no increase in cytotoxicity was observed over compound AR-1-122 which did not contain the methoxyaziridinyl moiety. 1a-c had the same sequence selectivity of alkylation as AR-1-122, showing alkylation only at 5'-TTTTGPu sequences. The relative binding to these sequences decreased with increasing number of methylene units. The addition of a methoxyaziridinyl moiety in this group of imidazole and BAM-containing compounds can, therefore, increase crosslinking ability to naked DNA but this does not result in an increase in cytotoxicity. In contrast the cytotoxicity was related to their ability to produce sequence specific alkylation at 5'-TTTTGPu sequences.

Structure-activity relationship of a series of C-terminus modified aminoalkyl, diaminoalkyl- and anilino-containing analogues of the benzoic acid mustard distamycin derivative tallimustine: synthesis, DNA binding and cytotoxicity studies

As part of our investigations into the design of more cytotoxic analogues of the experimental anticancer drug tallimustine, 1, C-terminus modified aminoalkyl-, 2a-c, diaminoalkyl-, 3, and anilino-containing, 4, derivatives have been synthesized. Compounds 2a-c differ by 2, 3, or 4 methylene units in the C-terminus, respectively. Results from an ethidium displacement study on poly(dA-dT), poly(dG-dC), calf thymus DNA and T4 coliphage DNA showed that compounds 2-4 interact in the minor groove of the polynucleotides with a preference for poly(dA-dT) over poly(dG-dC). Compound 4 bound more weakly to the DNAs than 2a-c and 3. Using a CD dilution assay compounds 2a-c and 3 were demonstrated to bind irreversibly to calf thymus DNA. The sequence selectivity by which compounds 2-4 alkylate DNA was demonstrated using a Taq polymerase stop assay. All the compounds alkylated preferentially at the 3'-purine residue in a 5'-TTTTGPu-3' sequence (Pu = A or G). This observed sequence specificity is similar to that of tallimustine and a related compound 5. At an equimolar concentration the aminoalkyl compounds 2a-c (2b > 2a > 2c), and diaminoalkyl compound 3 were more efficient at alkylating these sequences than the anilino compound 4. Following a one hour exposure of human chronic myeloid leukemia K562 cells, compounds 2b and 3 have lower IC50 values (1.64 microM and 3.03 microM, respectively) than tallimustine (5 microM) and similar values to a related compound 5 (2.2 microM). The order of cytotoxicity for all the compounds is 2b > 5 > 3 > 2a > 1 > 2c = 4. These results indicate that the cytotoxicities of these compounds are related to their relative ability to alkylate the consensus DNA binding sequence.