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.

Adherence to protocol in pregnant trauma patients? A 12-year retrospective study

PURPOSE

We investigated whether the standard (ATLS) trauma protocol was adhered to in cases of suspected multi-traumatized pregnant patients and if serious injuries were overlooked. We hypothesized that radiographic studies would be less frequent in pregnant trauma patients.

METHODS

Forty-eight pregnant trauma patients were received in the observational period from January 2000 until May 2012; median age 30 years (range 16-40) and median stage of pregnancy 22 weeks (range 4-40). A retrospective review of patient files was performed.

RESULTS

Twenty-one percent of the pregnant trauma patients received a full trauma CT (T-CT) scan (head to pelvis), which was significantly lower than the percentage (62 %) of all primarily referred trauma patients in the same period. In the last four years of observation, the use of radiographic studies among pregnant trauma patients increased considerably. Along with this increase in the tendency to use T-CT over time during the observational period, there was also a rise in the median ISS. In addition, radiographic studies of the pelvis and abdominal area were performed only half as frequently as studies of the neck and chest.

CONCLUSIONS

Adherence to the ATLS protocol in pregnant trauma patients was low in relation to radiographic studies but, in spite of this, no known significant injuries were missed. We found that a pelvic fracture seems to be predictive of a high risk of obstetric complications, such as intrauterine death or the need for cesarean section, but we were not able to relate trauma in general to a higher risk of cesarean section or premature birth.

[Pneumococcal meningitis. A 40-year case load]

Eighty-four cases of pneumococcal meningitis were admitted to the medical-epidemic department C, Odense Hospital, during the period from 1940 to 1980. 39% of the patients were under 10 years, 17% under one year, whereas 23% were over 50 years. The proportion males to females in all groups was approximately 3:2. Pneumococcal meningitis, like other types of meningitis, responds dramatically to antibiotic treatment, but must still be considered a serious disease. Following treatment with a combination of penicillin, streptomycin, sulphonamides and chloramphenicol the mortality during the period 1952 to 1980 decreased to 12.7%. The fatal cases after 1952 all occurred during the years 1975-77. Patients with meningitis are very sensitive to overhydration. It was therefore decided to restrict intravenous administration in these patients. Following the introduction of this regimen the mortality decreased again. The prevailing cause of death from meningitis during the antibiotic era was brain edema, which may occur even if the inflammation of the meninges has vanished. Therefore it is considered important to avoid overhydration in these patients.

[The analysis of polycyclics in vegetable samples]

PAH analyses in vegetables are often difficult to carry out; therefore two different clean-up methods, which allow elimination of interfering matrix components such as essential oils, waxes, carotinoids and chlorophylls were developed. Clean-up of 32 different vegetables samples consisted of either Bio-Beads S-X3 chromatography or semi-preparative HPLC on silica gel Si-60. PAH were determined by capillary GC-MS, which allowed the application of deuterium-labeled internal standards. The results are presented; higher PAH contamination was detected in kale and parsley.

Delayed attacks of malaria in visitors to the tropics

Out of 80 Danish college students and their teachers visiting the Middle East, West Pakistan, and India by bus in two four-month journeys during the summer and autumn of 1971, six individuals developed an apparently first attack of vivax malaria within seven to nine months after their return to Denmark. No cases of malaria were seen in the group during the journeys. Prophylaxis with chloroquine (Resochin) was strictly observed when visiting the areas in which malaria is endemic.All cases responded rapidly and completely to a full course of treatment with chloroquine. The most probable cause of the delay of the clinical manifestations is drug prophylaxis, which can prevent a clinical attack but not always eradicate the parasite.

Ischaemic heart disease in middle-aged men. Prevalence comparisons in Europe

The authors report the results of a collaborative study of the prevalence of ischaemic heart disease in 6 samples of middle-aged male clerical workers, drawn from 5 European countries and covering in all 4522 subjects. Detailed standardization of data-collection methods and of coding, analysis and tabulation was undertaken.Estimated prevalence rates for angina and history of possible infarction, based on the use of a standard questionnaire, showed significant variation between samples, but the validity of international comparisons of symptoms remains unproven. Prevalence rates for ischaemic-type ECG findings were high everywhere, and mostly showed no significant variation between the groups studied. Central coding of ECG findings proved essential to the making of unbiased comparisons. Neither the prevalence rates for symptoms nor those for ECG findings in these samples were recognizably correlated with the corresponding national mortality rates for ischaemic heart disease.Several possible risk factors were studied, but the only one found to be consistently associated with ischaemic heart disease was a raised blood pressure. Cigarette smoking was strongly associated with bronchitic symptoms and dyspnoea, but an association with heart disease was not demonstrated.