[Analysis of the failures of a cemented constrained liner model in patients with a high dislocation risk]

OBJECTIVE

To evaluate the short-term results of an ultra high molecular weight polyethylene retentive cup in patients at high risk of dislocation, either primary or revision surgery.

MATERIAL AND METHOD

Retrospective review of 38 cases in order to determine the rate of survival and failure analysis of a constrained cemented cup, with a mean follow-up of 27 months. We studied demographic data, complications, especially re-dislocations of the prosthesis and, also the likely causes of system failure analyzed.

RESULTS

In 21.05% (8 cases) were primary surgery and 78.95% were revision surgery (30 cases). The overall survival rate by Kaplan-Meier method was 70.7 months. During follow-up 3 patients died due to causes unrelated to surgery and 2 infections occurred. 12 hips had at least two previous surgeries done. It wasn't any case of aseptic loosening. Four patients presented dislocation, all with a 22 mm head (P=.008). Our statistical analysis didn't found relationship between the abduction cup angle and implant failure (P=.22).

CONCLUSIONS

The ultra high molecular weight polyethylene retentive cup evaluated in this series has provided satisfactory short-term results in hip arthroplasty patients at high risk of dislocation.

Comparison of bacterial results from conventional cultures of the periprosthetic membrane and the synovial or pseudocapsule during hip revision arthroplasty

INTRODUCTION

Bacterial identification is essential to diagnose and treat a revision for prosthetic loosening of an infected hip. The purpose of this study was to determine whether conventional cultures from the periprosthetic membrane are superior to synovial/pseudocapsule samples in the diagnosis of infection in hip revision arthroplasty.

MATERIALS AND METHODS

We performed a prospective study including all hip revisions from October 2009 to October of 2011. Once the implants were removed and prior to the administration of the antibiotic prophylaxis, six periprosthetic samples from different sites were sent to the laboratory for culturing: two periprosthetic fluid samples, two solid material (synovial/pseudocapsule) samples and two swabs. Once the six samples were taken, antibiotic prophylaxis was administered and just as the implant was removed, two more solid samples of the periprosthetic membrane were obtained.

RESULTS

Of a total of 86 hip revision surgeries, 22 were considered septic revisions postoperatively, of which 16 resulted in positive cultures. Of these 16 revisions, 14 obtained the same microbiologic diagnostic when considering either the synovial/pseudocapsule culture results or the solid membrane sample.

CONCLUSIONS

We conclude that the membrane sample for a conventional culture is not superior to the synovial/pseudocapsule sample in detecting microorganisms.

Antibacterial and antioxidant activities in extracts of fully grown cladodes of 8 cultivars of cactus pear

The antimicrobial and antioxidant activities of some cultivars of the nopal cactus have not been determined. In this study, 8 cultivars of nopal cacti from Mexico were assayed for phenolic content, antioxidant activities, and antimicrobial activities against Campylobacter Jejuni, Vibrio cholera, and Clostridium Perfringens. Plant material was washed, dried, and macerated in methanol. Minimum bactericidal concentrations (MBCs) were determined using the broth microdilution method. Antioxidant activities were quantitatively determined using spectrophotometric methods. The MCBs of the nopal cacti ranged from 1.1 to 12.5 mg/mL for c. jejuni, 4.4 to 30 mg/mL for V. cholera, and 0.8 to 16 mg/mL for C. perfringens in the cultivars Cardon Blanco, Real de Catorce, and Jalpa, respectively. High quantities of total phenols and total flavonoids were found in the Jalpa cacti (3.80 mg of gallic acid equivalent GAE/g dry weight [DW] and 36.64 mg of quercetin equivalents [QE]/g DW, respectively). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities (RSA) were correlated to bioactive compound contents. The Villanueva cacti had the highest %RSA at 42.31%, and the lowest activity was recorded in Copena V1 at 19.98%. In conclusion, we found that some of the 8 cactus pear cultivars studied may be used for their antioxidant compounds or antimicrobials to control or prevent the contamination of foods.

Changes in the brain and plasma Aβ peptide levels with age and its relationship with cognitive impairment in the APPswe/PS1dE9 mouse model of Alzheimer's disease

Double transgenic mice expressing mutant amyloid precursor protein (APPswe) and mutant presenilin 1 (PS1dE9) are a model of Alzheimer-type amyloidosis and are widely used in experimental studies. In the present work, the relationships between brain and plasma amyloid-β peptide (Aβ) levels and cognitive impairments were examined in male APPswe/PS1dE9 double transgenic mice at different ages. When compared with non-transgenic littermates, APPswe/PS1dE9 mice exhibited significant learning deficits from the age of 6months (M6), which were aggravated at later stages of life (M8 and M12). Sporadic brain amyloid plaques were observed in mice as early as M3 and progressively increased in number and size up to M12. A similar increase was observed in brain insoluble Aβ levels as assessed by enzyme-linked immunosorbent assay (ELISA). In particular, the levels of brain insoluble Aβ peptides rose steeply from M4 to M6. Interestingly, this pronounced amyloid deposition was accompanied by a temporary fall in the concentration of brain soluble and membrane-bound Aβ peptides at M6 that rose again at M8 and M12. The plasma levels of Aβ40 and Aβ42 decreased with advancing age up to M8, when they stabilized at M12. This decrease in plasma Aβ levels coincided with the observed increase in insoluble brain Aβ levels. These results could be useful for developing plasma Aβ levels as possible biomarkers of the cerebral amyloidosis and provide advances in the knowledge of the Aβ peptide biochemical changes that occur in the brain of Alzheimer's disease patients.

Duchenne muscular dystrophy in a developing country: challenges in management and genetic counseling

BACKGROUND AND OBJECTIVE

Multidisciplinary management of Duchenne Muscular Dystrophy (DMD) has achieved outstanding results in developed nations. We aimed to describe the status of diagnosis and management of DMD in a developing country through the experience of non-profit organizations.

METHODS

A Multistate, multiple-source, population-based survey was performed from medical records of 432 patients. Data were retrospectively collected, reviewed and curated by health specialists; including clinical features, age at first symptoms, age at diagnosis, disease progression and management, family history, education, age and cause of death.

RESULTS

There is a delay in noticing first symptoms and it did not diminish over the past 20 years. Less than 30% of patients obtained definite diagnosis and most of them are in physiotherapy programs but not under steroid treatment. In our study, family history does not anticipate recognition of symptoms compared to sporadic cases (p = 0.05). Approximately 93.33% of our patients attended to education programs. Mean age at death was 18.94 +/- 6.73 years and the most frequent cause was pneumonia.

CONCLUSION

Delayed diagnosis of DMD in Mexico is mainly caused by the late detection of first symptoms. There is no difference in early detection of symptoms between familiar and sporadic cases. Lifespan of patients in our cohort is reduced compared to developed countries. The late diagnosis and low percentage of definite cases may affect patient management and genetic counseling and could also preclude participation of patients into novel clinical trials.

Predicting mixed-gas adsorption equilibria on activated carbon for precombustion CO2 capture

We present experimentally measured adsorption isotherms of CO2, H2, and N2 on a phenol-formaldehyde resin-based activated carbon, which had been previously synthesized for the separation of CO2 in a precombustion capture process. The single component adsorption isotherms were measured in a magnetic suspension balance at three different temperatures (298, 318, and 338 K) and over a large range of pressures (from 0 to 3000-4000 kPa). These values cover the temperature and pressure conditions likely to be found in a precombustion capture scenario, where CO2 needs to be separated from a CO2/H2/N2 gas stream at high pressure (~1000-1500 kPa) and with a high CO2 concentration (~20-40 vol %). Data on the pure component isotherms were correlated using the Langmuir, Sips, and dual-site Langmuir (DSL) models, i.e., a two-, three-, and four-parameter model, respectively. By using the pure component isotherm fitting parameters, adsorption equilibrium was then predicted for multicomponent gas mixtures by the extended models. The DSL model was formulated considering the energetic site-matching concept, recently addressed in the literature. Experimental gas-mixture adsorption equilibrium data were calculated from breakthrough experiments conducted in a lab-scale fixed-bed reactor and compared with the predictions from the models. Breakthrough experiments were carried out at a temperature of 318 K and five different pressures (300, 500, 1000, 1500, and 2000 kPa) where two different CO2/H2/N2 gas mixtures were used as the feed gas in the adsorption step. The DSL model was found to be the one that most accurately predicted the CO2 adsorption equilibrium in the multicomponent mixture. The results presented in this work highlight the importance of performing experimental measurements of mixture adsorption equilibria, as they are of utmost importance to discriminate between models and to correctly select the one that most closely reflects the actual process.

[Septic arthritis of the hip by Haemophilus Influenzae type F in childhood: a case report]

Septic arthritis of the hip is an acute infection, predominantly of bacterial etiology. Although Staphylococcus aureus is the primary pathogen in any age group, other potentially pathogenic microorganisms exist. We describe the case of an 18-month patient with septic arthritis of the hip with a rare causal agent (Haemophilus influenzae type F) and a good outcome. This case highlights the importance of considering other less common etiologic agents for septic arthritis in children, performing arthrocentesis with synovial fluid culture before starting antibiotic treatment, whenever this is possible. In addition, as in this case, it should be noted that a positive synovial fluid culture for Haemophilus influenzae forces typification of the bacteria in order to rule out or confirm a vaccine failure.

[Study of the consistency of a system for preoperative planning digital in total arthroplasty of the hip]

OBJECTIVE

Check the agreement of a preoperative digital templating, compared with the final result in the postoperative radiograph.

MATERIAL AND METHOD

The study was carried out on a 55 total hip prosthesis. A templating-software Neteous (Socincer, Gijón, Spain) was used. Agreement was measured using the Kappa Index for the stem offset or Lin Index for others variables: stem size, cup size, femoral neck length, and the distance from the center of rotation of the femoral head to the lesser trochanter. The percentage of accurate hits was also described.

RESULTS

Stem size: The exact success or error of only one size was of 61.6%. Quantitatively the Lin Index was 0.64 (substantial). Horizontal offset: satisfactory agreement was obtained (Kappa index of 0.75). In 6 cases (10.90%) was changed to lateralized during surgery, for more joint stability. Size of the cup: the agreement obtained was 0.67 (substantial) with a hit grade of 43.6%. Prosthetic neck length: the exact hit or error of only one size were found in 50.9%, moderate level of agreement. Distance from the center of rotation to the lesser trochanter: was observed for almost perfect agreement with Lin Index of 0.95. The exact percentage of hits or gap error less than 5mm was 74.5%.

DISCUSSION AND CONCLUSION

In ours hands, the preoperative templating software analyzed, has provided acceptable agreement rates, when compared with the postoperative result. But it takes more works verified by independent observers.

Magnetic and thermal responses triggered by structural changes in the double perovskite Sr2YRuO6

Among double perovskites, the interpretation of the magnetic, thermal and transport properties of Sr(2)YRuO(6) remains a challenge. Characterization using different techniques reveals a variety of features that are not understood, described as anomalous, and yields contradictory values for several relevant parameters. We solved this situation through detailed susceptibility, specific heat, thermal expansion and x-ray diffraction measurements, including a quantitative correlation of the parameters characterizing the so-called anomalies. The emergence of short-range magnetic correlations, surviving well above the long-range transition, naturally accounts for the observed unconventional behavior of this compound. High resolution x-ray powder diffraction and thermal expansion results conclusively show that the magnetic and thermal responses are driven by lattice changes, providing a comprehensive scenario in which the interplay between the spin and structural degrees of freedom plays a relevant role.