Pharmacokinetics of gentamicin eluted from a regenerating bone graft substitute: In vitro and clinical release studies

Objectives

Deep bone and joint infections (DBJI) are directly intertwined with health, demographic change towards an elderly population, and wellbeing.

The elderly human population is more prone to acquire infections, and the consequences such as pain, reduced quality of life, morbidity, absence from work and premature retirement due to disability place significant burdens on already strained healthcare systems and societal budgets.

DBJIs are less responsive to systemic antibiotics because of poor vascular perfusion in necrotic bone, large bone defects and persistent biofilm-based infection. Emerging bacterial resistance poses a major threat and new innovative treatment modalities are urgently needed to curb its current trajectory.

Materials and Methods

We present a new biphasic ceramic bone substitute consisting of hydroxyapatite and calcium sulphate for local antibiotic delivery in combination with bone regeneration. Gentamicin release was measured in four setups: 1) in vitro elution in Ringer’s solution; 2) local elution in patients treated for trochanteric hip fractures or uncemented hip revisions; 3) local elution in patients treated with a bone tumour resection; and 4) local elution in patients treated surgically for chronic corticomedullary osteomyelitis.

Results

The release pattern in vitro was comparable with the obtained release in the patient studies. No recurrence was detected in the osteomyelitis group at latest follow-up (minimum 1.5 years).

Conclusions

This new biphasic bone substitute containing antibiotics provides safe prevention of bone infections in a range of clinical situations. The in vitro test method predicts the in vivo performance and makes it a reliable tool in the development of future antibiotic-eluting bone-regenerating materials.

Cite this article: M. Stravinskas, P. Horstmann, J. Ferguson, W. Hettwer, M. Nilsson, S. Tarasevicius, M. M. Petersen, M. A. McNally, L. Lidgren. Pharmacokinetics of gentamicin eluted from a regenerating bone graft substitute: In vitro and clinical release studies. Bone Joint Res 2016;5:427–435. DOI: 10.1302/2046-3758.59.BJR-2016-0108.R1.

Evaluation of an accident and emergency teleconsultation service for north-east Scotland

We evaluated an accident and emergency teleconsultation service provided to 14 community hospitals in north-east Scotland. Each community hospital was equipped with a videoconferencing system and a document camera to allow transmission of radiographs. The network used 384 kbit/s ISDN connections. A total of 1392 teleconsultations were recorded during a 12-month study period. Seventy-seven per cent of patients ( n = 1072) were managed locally and 23% ( n = 320) were transferred to Aberdeen. The majority (95%) of teleconsultations were conducted on weekdays, and 90% of these occurred between the hours of 09:00 and 16:00. The mean delay in contacting a doctor was 9 min and the mean consultation time was 10 min. The majority of patients were suffering from fractures or suspected fractures of the limbs. Radiograph transmission was used in 75% of all teleconsultations. A high degree of satisfaction was recorded by all users of the service.

Preliminary comparison of primary and conversion surgery with magnetically controlled growing rods in children with early onset scoliosis

PURPOSE

Non-invasive distraction of magnetically controlled growing rods (MCGR) avoids repeated surgical lengthening in patients with early onset scoliosis, but it is not known how effective this technique is in previously operated children.

METHODS

In a retrospective, multicentre study, the data were obtained for 27 primary (P) patients [mean age 7.0 (2.4-10.7) years at surgery] and 23 conversion (C) patients [mean age 7.7 (3.6-11.0) years at conversion from standard growing rods] with 1-year follow-up.

RESULTS

The mean major curve was 63.9° in the P group and 46.5° in the C group at baseline (preoperatively, p = 0.0009) and 39.5° and 39.6°, respectively, at 1-year follow-up (p = 0.99). The mean percentage change of spinal growth from baseline to 1-year follow-up was 18.3 % in the P group and 6.5 % in the C group (p = 0.007). Comparing the spinal growth from postoperative to 1-year follow-up no statistical difference was observed between the study groups (1.8 % P vs -2.2 % C, p = 0.09).

CONCLUSIONS

Scoliosis can be equally controlled after conversion from traditional growing rods into MCGR, but spinal growth from baseline is less in the conversion patients as compared with the primary group.

LEVEL OF EVIDENCE

III.

Response of an Impact Test Apparatus for Fall Protective Headgear Testing Using a Hybrid-III Head/Neck Assembly

A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury.

A MultiCenter Pilot Randomized Controlled Trial of Remote Ischemic Preconditioning in Major Vascular Surgery

A pilot randomized controlled trial that evaluated the effect of remote ischemic preconditioning (RIPC) on clinical outcomes following major vascular surgery was performed. Eligible patients were those scheduled to undergo open abdominal aortic aneurysm repair, endovascular aortic aneurysm repair, carotid endarterectomy, and lower limb revascularization procedures. Patients were randomized to RIPC or to control groups. The primary outcome was a composite clinical end point comprising any of cardiovascular death, myocardial infarction, new-onset arrhythmia, cardiac arrest, congestive cardiac failure, cerebrovascular accident, renal failure requiring renal replacement therapy, mesenteric ischemia, and urgent cardiac revascularization. Secondary outcomes were components of the primary outcome and myocardial injury as assessed by serum troponin values. The primary outcome occurred in 19 (19.2%) of 99 controls and 14 (14.1%) of 99 RIPC group patients ( P = .446). There were no significant differences in secondary outcomes. Our trial generated data that will guide future trials. Further trials are urgently needed.

The phototoxicity of vemurafenib: An investigation of clinical monochromator phototesting and in vitro phototoxicity testing

BACKGROUND

Vemurafenib is a targeted therapy approved for the treatment of patients with metastatic melanoma harbouring the BRAF V600E mutation. Photosensitivity has been reported in over 50% of patients and has been demonstrated to involve at least the broadband UVA spectrum in most patients. Erythrocyte protoporphyrin levels have also been reported as elevated in some patients.

OBJECTIVES

We report the results of monochromator phototesting in one patient recorded before and while taking vemurafenib. Analysis of porphyrin levels was also conducted.

RESULTS

After one month of vemurafenib therapy the patient demonstrated markedly increased light sensitivity in the UVA spectrum between 335 ± 27 nm, 365 ± 27 nm and 400 ± 27 nm. However responses in the UVB (305 ± 5 nm) and blue light (430 ± 27 nm) regions were normal. There was no abnormal immediate erythemal response. Pre-vemurafenib baseline phototesting was normal, as was repeat testing two months later when the patient was taking high doses of systemic steroid. No abnormal porphyrins were detected and the antinuclear antibody test was normal. In parallel studies, HaCaT keratinocytes incubated with vemurafenib were killed by UVA but not by visible (blue) light and did not show evidence of detectable intracellular porphyrin in the presence of the drug.

CONCLUSION

These data confirm vemurafenib induced UVA photosensitivity with a probable phototoxic mechanism not mediated via enhanced porphyrin.

A cohort study of influences, health outcomes and costs of patients' health-seeking behaviour for minor ailments from primary and emergency care settings

OBJECTIVES

To compare health-related and cost-related outcomes of consultations for symptoms suggestive of minor ailments in emergency departments (EDs), general practices and community pharmacies.

DESIGN

Observational study; prospective cohort design.

SETTING

EDs (n=2), general practices (n=6) and community pharmacies (n=10) in a mix of rural/urban and deprived/affluent areas across North East Scotland and East Anglia. Participants Adults (≥18 years) presenting between 09:00 and 18:00 (Monday-Friday) in general practices and 09:00-18:00 (Monday-Saturday) in pharmacies and EDs with ≥1 of the following: musculoskeletal pain; eye discomfort; gastrointestinal disturbance; or upper respiratory tract-related symptoms.

INTERVENTIONS

Participants completed three questionnaires: baseline (prior to index consultation); satisfaction with index consultation and follow-up (2 weeks after index consultation).

MAIN OUTCOME MEASURES

Symptom resolution, quality of life, costs, satisfaction and influences on care-seeking behaviour.

RESULTS

377 patients participated, recruited from EDs (81), general practices (162) and community pharmacies (134). The 2-week response rate was 70% (264/377). Symptom resolution was similar across all three settings: ED (37.3%), general practice (35.7%) and pharmacy (44.3%). Mean overall costs per consultation were significantly lower for pharmacy (£29.30 (95% CI £21.60 to £37.00)) compared with general practice (£82.34 (95% CI £63.10 to £101.58)) and ED (£147.09 (95% CI £125.32 to £168.85)). Satisfaction varied across settings and by measure used. Compared with pharmacy and general practice use, ED use was significantly (p<0.001) associated with first episode and short duration of symptom(s), as well as higher levels of perceived seriousness and urgency for seeking care. Convenience of location was the most common reason for choice of consultation setting.

CONCLUSIONS

These results suggest similar health-related outcomes and substantially lower costs with pharmacy consultations for minor ailments. Effective strategies are now needed to shift demand for minor ailment management away from EDs and general practices to the community pharmacy setting.

From adaptive licensing to adaptive pathways: delivering a flexible life-span approach to bring new drugs to patients

The concept of adaptive licensing (AL) has met with considerable interest. Yet some remain skeptical about its feasibility. Others argue that the focus and name of AL should be broadened. Against this background of ongoing debate, we examine the environmental changes that will likely make adaptive pathways the preferred approach in the future. The key drivers include: growing patient demand for timely access to promising therapies, emerging science leading to fragmentation of treatment populations, rising payer influence on product accessibility, and pressure on pharma/investors to ensure sustainability of drug development. We also discuss a number of environmental changes that will enable an adaptive paradigm. A life‐span approach to bringing innovation to patients is expected to help address the perceived access vs. evidence trade‐off, help de‐risk drug development, and lead to better outcomes for patients.

Factors influencing escalation of care by junior medical officers

Patients can acutely deteriorate unexpectedly. Junior medical officers (JMOs) are often first to review patients who become unwell. Opportunities to escalate care to a senior colleague may exist prior to the need for a rapid response team review. Little is known about the factors that influence JMO decisions to escalate care. In this study, our objective was to investigate the self-reported factors that influence escalation of care by JMOs in a university-affiliated, tertiary level hospital. We designed a face-to-face questionnaire of JMOs using standardised introduction to minimise interviewer bias. Fifty JMOs participated in the study (a 100% response rate). Most (63.3%) felt that they would be able to identify a clinically deteriorating patient. They would be more likely to escalate care if they were not familiar with the patient's clinical problem. If handover plans were seen to be adequate, JMOs felt it was less necessary to escalate care. Few JMOs (12%) agreed that they limited escalation due to fear of criticism or fear of conflict with senior medical staff. Although 36% agreed that they were concerned about waking seniors overnight, only 6% feared that escalating care overnight would affect their future career prospects. Escalation of care appears to be mostly influenced by the confidence and familiarity of the JMO with the cause of deterioration. JMOs identified clear handover with documented goals of treatment and suggested actions in event of clinical deterioration as the best means by which to improve the process of escalation of care for clinically deteriorating patients.

Transferrin saturation ratio and risk of total and cardiovascular mortality in the general population

BACKGROUND

The transferrin saturation (TSAT) ratio is a commonly used indicator of iron deficiency and iron overload in clinical practice but precise relationships with total and cardiovascular mortality are unclear.

PURPOSE

To better understand this relationship, we explored the association of TSAT ratio (serum iron/total iron binding capacity) with mortality in the general population.

METHODS

The relationships of TSAT ratio with total and cardiovascular mortality were explored in 15 823 subjects age 20 and older from the Third National Health and Nutrition Examination Survey (1988-94). All subjects had vital status assessed through to 2006.

RESULTS

During follow-up, 9.7% died of which 4.4% were from cardiovascular disease. In unadjusted analysis, increasing TSAT ratio was inversely associated with mortality. With adjustment for baseline demographic and clinical characteristics, the TSAT-mortality relationship followed a j-shaped pattern. Compared with the referent group [ratio 23.7-31.3%: hazard ratio (HR) =1.00], subjects in the lowest two quartiles, <17.5 % and 17.5-23.7 %, experienced significantly higher mortality risks of 1.45 (1.19-1.77) and 1.27 (1.06-1.53), respectively, whereas subjects in the highest quartile, >31.3 %, experienced significantly higher mortality risks of 1.23 (1.01-1.49). The pattern of association was more pronounced for cardiovascular mortality with significantly higher mortality risks for the lowest two quartiles [HR = 2.09 (1.43-3.05) and 1.90 (1.33-2.72), respectively] and highest quartile HR = 1.59 (1.05-2.40).

CONCLUSIONS

Both low and high TSAT ratios are significantly and independently associated with increased total and cardiovascular mortality. The optimal TSAT ratio associated with the greatest survival is between 24% and 40%.

Photodynamic therapy in dermatology: Dundee clinical and research experience

Topical photodynamic therapy (PDT) is increasingly accepted and used as a highly effective treatment for superficial non-melanoma skin cancer and dysplasia. We describe the developments in topical PDT for the treatment of skin diseases in our own PDT Centre in Dundee, both clinically and from a research base. Improvements in PDT could be achieved by optimisation of photosensitiser and light delivery, and these goals underpin the aims of our centre. We hope to facilitate the dissemination of use of PDT in dermatology throughout Scotland and outline some of the progress in these areas.

Review of an established UK home phototherapy service 1998-2011: improving access to a cost-effective treatment for chronic skin disease

OBJECTIVES

To review the Tayside home phototherapy service, including numbers of patients treated, diagnoses and outcomes, side-effects and safety, cost-effectiveness and absolute costs. To consider why home or outpatient phototherapy is not available to all patients who might benefit and how this could be addressed.

STUDY DESIGN

Observational and cost analysis.

METHODS

Analysis of the Tayside home phototherapy database 1998 and 2011, home phototherapy patient questionnaires, outcome data, costs and a comparison with outpatient phototherapy. Review of literature and current national guidelines for phototherapy, traditional systemic and biologic therapies for psoriasis.

RESULTS

298 courses of home narrowband UVB (NB-UVB) phototherapy were undertaken by 212 patients between 1998 and 2011, five courses in 1998 increasing to 36 in 2011. The main diagnoses treated were psoriasis (72%), atopic dermatitis (8%), and desensitization of photodermatosis (7%). For psoriasis, 74.5% achieved clearance or minimal residual activity in a median of 30 exposures (range 10-60). The estimated costs to the hospital ranged from £229 to £314 per course (£307 to £422 per effective course for psoriasis), compared with £114 for out-patient therapy (£149 per effective course for psoriasis). The total cost to society (hospital and patient costs) is around £410 per course, compared to an estimated £550 for outpatient therapy for this group of patients. Treatment was well tolerated, erythema rates were similar to outpatient therapy, there were no complaints and the vast majority would choose home over outpatient phototherapy if required in the future.

CONCLUSIONS

Hospital supervised home phototherapy appears as safe and effective as outpatient therapy and provides equality of access for patients who cannot attend for outpatient therapy. These patients may otherwise be inadequately treated or given more costly and higher risk systemic therapies, particularly for psoriasis. Commissioners and clinicians involved in dermatology services should provide accessible phototherapy for all patients who might benefit, utilizing home phototherapy where outpatient access is not possible.