Detection of biomaterial-associated infections in orthopaedic joint implants

Biomaterial-associated infection of orthopaedic joint replacements is the second most common cause of implant failure. Yet, the microbiologic detection rate of infection is relatively low, probably because routine hospital cultures are made only of swabs or small pieces of excised tissue and not of the surfaces of potentially infected implants. Joint replacements from patients in whom infection was suspected, after clinical, radiologic, and biochemical examinations, were used in this study. The aim of the current study was to compare the detection rate of infection in total joint replacements based on cultures of the excised tissue and scrapings from the biomaterial surface. Joint prostheses were retrieved from 22 patients requiring orthopaedic revision surgery because of suspected infection of their prostheses. Routine hospital culturing of tissue only showed bacterial growth in nine patients (41%). However, after prolonged culturing, bacterial growth was observed in 14 patients (64%), whereas extensive culturing of scrapings from the biomaterial surface indicated bacterial growth in 19 of the 22 patients (86%). In addition, confocal laser scanning microscopy enabled observation of biofilm bacteria on the surfaces of the explanted prostheses. Diagnosis in orthopaedic revision surgery should consider using a microbial or microscopic analysis of the surface of an explanted prosthesis, where the biofilm mode of growth firmly anchors and protects the infecting organisms. Improved detection of infection by analysis of the implant surface is expected to yield ameliorated therapy and a reduced need for revision surgery.     

Viscoelastic behavior and structural properties of the coracoclavicular ligaments

During contact sports such as football, hockey or rugby, the coracoclavicular ligaments are commonly ruptured. Currently, the limited biomechanical data on the properties and function of these ligaments have led to debate on the "gold standard" treatment for these injuries. Therefore, the objective of this study was to characterize the geometry, viscoelastic behavior and structural properties of the coracoclavicular ligaments (n=11). The trapezoid and conoid were found to have similar length (9.6+/-4.4 vs. 11.2+/-4.1 mm) and cross-sectional area (103+/-43 vs. 69+/-51 mm2), respectively (P>0.05). Static and cyclic stress relaxation tests were then performed, followed by uniaxial tensile testing with the insertions of each ligament aligned to ensure a uniform distribution of load across the fibers. No significant differences were observed for the trapezoid and conoid during the static (36+/-8% vs. 31+/-7%) and cyclic (23+/-12% vs. 16+/-6%) stress relaxation tests, respectively (P>0.05). Similarly, no statistically significant differences were found between the trapezoid and conoid for linear stiffness (83+/-40 vs. 70+/-23 N mm(-1)), ultimate load (312+/-133 vs. 266+/- 108 N), energy absorbed at failure (820+/-576 vs. 752+/- 410 N mm), percent elongation (74+/-47% vs. 62+/-22%) and elongation at failure (5.8+/-2.2 vs. 6.1+/-1.6 mm), respectively (P>0.05). A comparison of our data to previous studies suggests that the complex fiber orientation of these ligaments has a significant role in determining the maximum load that can be transferred between the clavicle and scapula by each bone-ligament-bone complex. Our findings also further confirm the functional role of the coracoclavicular ligaments in supporting the upper extremity, and provide data for reconstruction and rehabilitation protocols as well as computational models.     

Anesthesia with propofol, remifentanil and cisatracurium in renal transplantation

A 41-year-old woman with end-stage renal insufficiency in peritoneal dialysis for 3 years received a kidney transplant under anesthesia with remifentanil, propofol, and cisatracurium. She had a history of hypertension and was being treated with enalapril, metoprolol and erythropoietin. After anesthetic induction, blood pressure fell significantly and surgery was performed in a context of hemodynamic stability. The postoperative course was good, with a functional graft and adequate diuresis from the start. Anesthetics with minimal residual effects and as little renal toxicity as possible are ideal for use in kidney transplantation. The drugs used in this case had pharmacokinetic and pharmacodynamic properties that make them particularly appropriate for such patients.     

Liver transplantation and transjugular intrahepatic portosystemic shunt

OBJECTIVE: Describe the results of liver transplantation after installing Transjugular Intrahepatic Portosystemic Shunt (TIPS) and compare them with those of a control group in a comparative, longitudinal, retrospective study. MATERIALS AND METHODS: Between April 1986 and October 2002, we performed 875 liver transplantations. Between January 1996 and October 2002, 26 transplantations were performed on TIPS carriers. This group was compared with a control cohort of 50 randomly selected patients who underwent transplantation in this period (non-TIPS carriers). Both groups were homogeneous with no significant differences between age, sex United Network for Organ Sharing (UNOS) score, Child stage, or etiology. RESULTS: Actuarial survival rates at 1 and 3 years: TIPS group 96.15% and 89.29% versus control cohort 87.8% and 81%, respectively. In 73.9%, the TIPS was clearly effective; in 88.9%, a postoperative Doppler revealed normal flow. There were no statistically significant differences compared with time on the waiting list for transplant, duration of the operation, ischemia times, intraoperative consumption of hemoderivates, vascular or nonvascular postoperative complications, duration of stay in the intensive care unit, hospital stay, or retransplantation rate. CONCLUSIONS: In our experience, TIPS insertion does not affect either the intraoperative or postoperative evolution and is not associated with an increased time on the liver transplant waiting list.     

Irinotecan in the treatment of advanced colorectal cancer in patients pretreated with Fluorouracil-based chemotherapy: a study to determine recommendable therapeutic dosage

Because no consensus exists regarding recommendable dose levels for irinotecan, an intrapatient dose escalation phase I-II study was initiated in previously treated patients with colorectal cancer. Survival was a secondary endpoint. Thirty-five consecutive patients with progressive disease after 5-fluorouracil-based chemotherapy were enrolled to receive irinotecan starting from 250 mg/m2/3 weeks and rising to currently used therapeutic doses. In total, 162 cycles were administered. The median tolerable dose was 250 mg/m2. Twelve patients (34%) were unable to tolerate doses greater than 250 mg/m2, 10 patients (28%) presented toxicity at 250 mg/m2 and 2 patients tolerated only 200 mg/m2. Three patients (9%) had partial response. The major adverse reactions were grade III-IV diarrhea, grade II-III nausea/vomiting, grade II-III neutropenia, and grade II-III anaemia in 28%, 48%, 11%, and 17% of the patients, respectively. Median survival time and time to progression were 8 and 3 months, respectively. The current irinotecan dose of 350 mg/m2/3 weeks appears unacceptably toxic and, hence, a lower dose needs to be considered. The response rates obtained are similar to the results observed in phase III studies, and its activity appears not to be adversely affected with this treatment scheme.     

Exposure to soil contaminated with an environmental PCB/PCDD/PCDF mixture modulates ultraviolet radiation-induced non-melanoma skin carcinogenesis in the Crl:SKH1-hrBR hairless mouse

Chlorinated aromatic contaminants are active in carcinogenic processes within the skin and may have the potential to modulate ultraviolet radiation (UV)-induced skin carcinogenesis. Exposure to a complex environmental PCB/PCDD/PCDF mixture (polychlorinated biphenyls/polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans) during the irradiation phase of photocarcinogenesis was associated with significant (P < or = 0.001) reductions in papilloma incidence and squamous cell carcinoma multiplicity at irradiated skin sites. This protective effect was associated with significantly (P < 0.0001) reduced chronic epidermal thickening in UV and contaminant-exposed mice compared with mice exposed to UV only. Contaminant exposure was also associated with increased UV absorbance of skin methanol extracts implying a sunscreen-like effect.     

Usefulness of thallium-201 SPECT scintimammography to differentiate benign from malignant breast masses in mammographically dense breasts

The purpose of this study was to assess the usefulness of thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) scintimammography to differentiate benign from malignant breast masses in 32 female Taiwanese patients with indeterminate mammographic probability of malignancy because of mammographically dense breasts. All breast masses were removed, and final histopathological diagnoses were obtained in all cases. The results showed that thallium-201 SPECT scintimammography findings were true-positive in 22 cases, false-positive in 1 case, true-negative in 7 cases, and false-negative in 2 cases. The diagnostic sensitivity, specificity, and accuracy were 91.7%, 87.5%, and 90.6%, respectively, for detecting breast cancer in mammographically dense breasts. In conclusion, thallium-201 SPECT scintimammography is a useful tool for differentiating benign from malignant breast masses in patients with indeterminate mammograms because of mammographically dense breasts.     

Assessing communication competence in an online study: toward informing subsequent interventions among older adults with cancer,their lay caregivers,and peers

Employing quantitative and qualitative measures, online and paper versions, we tested Kreps's (1988) relational health communication model by examining relations among social support, communication competence, and perceived stress in a study of well-elders, elderly individuals with cancer, and their lay caregivers (N = 76). Grounding the qualitative part of the study in the narrative paradigm (Fisher, 1984), we used the critical incident technique (Flanagan, 1954) to collect participant narratives focusing on positive and negative expressions of social support. The results indicated partial support for the relational health communication model. In particular, participants who were more communicatively competent were found to have lower levels of perceived stress, and they were more satisfied with the support offered by members of their support network. In addition, the critical incidents revealed that participants received significantly more emotional and esteem support from their network than other social support types. Key limitations and future directions are also identified.