Comparison of in vitro activities of meropenem productions on Klebsiella pneumoniae isolated from hospitalized patients

Purpose: Antimicrobial activities of meropenem products on Klebsiella pneumoniae isolates were determined. Methods: 212 non-duplicated Klebsiella pneumoniae isolates were examined for in vitro meropenem susceptibility test by using the following disks, which were made from Meronem (AstraZeneca, UK), Exipenem (Exir, Iran) and Meroxan (DAANA, Iran) powders. MIC₅₀ and MIC₉₀ for meropenem antibiotics were determined.Results: Meronem had good activities against most isolates of Klebsiella pneumoniae, and only a few strains had a rather high MIC. Exipenem and Meroxan showed a similar activity with Meronem. Conclusion: Regarding the comparison of two internal generic meropenem products with the external Meronem product have shown that they are equivalents in terms of microbiological activity, as measured using the disk diffusion and MIC. In developing countries, we suggested preparing disks with antibiotic powders that can be an equivalent function in microbiological activity with standard disks. In addition, since it demonstrated significant antimicrobial activity against the Klebsiella pneumoniae. For use of Exipenem and Meroxan in vivo, it would be better to perform additional testing (activity against different species, stability etc.).     

Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture

Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.     

How Does a Novel Monoplanar Pedicle Screw Perform Biomechanically Relative to Monoaxial and Polyaxial Designs?

Background

Minimally invasive spinal fusions frequently require placement of pedicle screws through small incisions with limited visualization. Polyaxial pedicle screws are favored due to the difficulty of rod insertion with fixed monoaxial screws. Recently, a novel monoplanar screw became available that is mobile in the coronal plane to ease rod insertion but fixed in the sagittal plane to eliminate head slippage during flexion loads; however, the strength of this screw has not been established relative to other available screw designs.

Questions/purposes

We compared the static and dynamic load to failure in polyaxial, monoaxial, and monoplanar pedicle screws.

Methods

Six different manufacturers’ screws (42 total) were tested in three categories (polyaxial, n = 4; monoaxial, n = 1; monopolar, n = 1) utilizing titanium rods. An additional test was performed using cobalt-chromium rods with the monopolar screws only. Screws were embedded into polyethylene blocks and rods were attached using the manufacturers’ specifications. Static and dynamic testing was performed. Dynamic testing began at 80% of static yield strength at 1 Hz for 50,000 cycles.

Results

In static testing, monoaxial and monoplanar screws sustained higher loads than all polyaxial screw designs (range, 37%–425% higher; p < 0.001). The polyaxial screws failed at the head-screw interface, while the monoaxial and monoplanar screws failed by rod breakage in the static test. The dynamic loads to failure were greater with the monoplanar and monoaxial screws than with the polyaxial screws (range, 35%–560% higher; p < 0.001). With dynamic testing, polyaxial screws failed via screw-head slippage between 40% and 95% of static yield strength, while failures in monoaxial and monoplanar screws resulted from either screw shaft or rod breakage.

Conclusions

All polyaxial screws failed at the screw-head interface in static and dynamic testing and at lower values than monoaxial/monoplanar screw designs. Monoplanar and monoaxial screws failed at forces well above expected in vivo values; this was not the case for most polyaxial screws.

Clinical Relevance

Polyaxial screw heads slip on the screw shank at lower values than monoaxial or monoplanar screws, and this results in angular change between the rod and pedicle screw, which could cause loss of segmental lordosis. The novel monoplanar screw used in this study may combine ease of rod placement with sagittal plane strength.     

Early complications of surgery in operative treatment of ankle fractures in those over 60: A review of 186 cases

Introduction

Ankle fractures are among the most common injuries of the lower extremity encountered by orthopaedic surgeons. With increasing population age and osteoporosis, the prevalence of these fractures is expected to increase. The aim of this study was to evaluate complications and the need for revision surgery after the surgical treatment of ankle fractures in patients over 60 years of age. We report the outcomes of 186 consecutive patients who underwent operative treatment for rotational ankle fractures in our institution from 2007 to 2010.

Materials and methods

Data were collected retrospectively for the purpose of this study. The outcome measures included minor complications which did not need further surgical intervention, that is, superficial wound infections, delayed wound healing, prominent implants and skin irritation, and major complications that prompted surgical intervention (due to deep wound infection, loosening of implants or loss of fixation). Medical complications were also recorded. Long-term complications (postoperative osteoarthritis) were not assessed in this study. Logistic regression analysis and Fisher's exact test were used to identify factors predicting higher risk of complications.

Results

The average age was 70.67 years (standard deviation (SD) 7.40). There were 132 (71%) females and 54 (29%) males. The overall rate of complications was 21.5% with 10.8% of them being major complications prompting surgical intervention for wound washout, removal of implants and revision of fixation. Statistical analysis showed that smoking, age, diabetes, local factors (osteopaenia, peripheral neuropathy, peripheral vascular disease, lymphoedema and venous insufficiency) and modified Charlson score were significantly associated with occurrence of complications. Gender had a marginally significant effect. Coronary artery disease and fracture type (Weber classification) did not have a significant effect on the outcome.

Discussion and conclusion

Our data show that surgical treatment of ankle fractures in the elderly is associated with a high rate of complications. The factors predicting a high rate of complications include smoking, age, diabetes, local factors and a higher modified Charlson score. It is important to bear the factors in mind whilst deciding whether surgical treatment should be used in the treatment of such fractures in the elderly and explains these to patients at the time of obtaining consent. Further large-scale studies are needed to validate the predictive value of the suggested modified Charlson score.     

The epidemiology of end-stage renal disease in Iran in an international perspective.

INTRODUCTION: The epidemiology of end-stage renal disease (ESRD) and renal replacement therapy (RRT) is under continuous evolution all over the world. We report here the epidemiological analysis of ESRD and RRT in Iran and discuss it against the background of the international situation. METHODS: This epidemiological report is based on data from centre questionnaires which were collected in Iran from 1997 onwards, with a response rate of 100%. RESULTS: The prevalence/incidence of RRT patients were 238/49.9 p.m.p. in the year 2000. Haemodialysis and kidney transplantation were the most common RRT modalities, accounting for 53.7% and 45.5% of prevalent RRT patients, respectively. The proportion treated by peritoneal dialysis was very low (<1%). Home haemodialysis was not performed. The majority of haemodialysis centres used synthetic membranes (70%) and 100% of the sessions were performed using acetate as a buffer; 42.5% of haemodialysis patients were treated with a twice-weekly regimen, whilst 49.6% were on the standard thrice-weekly regimen. The majority of RRT patients in Iran were young to middle aged. The great majority of renal allografts came from living donors (mainly unrelated to recipients). The main renal diseases leading to ESRD were diabetes and hypertension. The third most common category was "cause unknown". CONCLUSION: The epidemiology of RRT in Iran is characterized by: (i) young patient age (younger than the international average); (ii) high proportion of patients receiving renal allograft; (iii) use of living-unrelated donors as the major source of renal allografts.     

Methotrexate-induced acral erythema with bullous reaction

Chemotherapy-induced acral erythema (CIAE), a toxic reaction to a number of different chomotherapeutic agents, causes a symmetrical, painful erythema of both the palms and soles which is self-limiting. The association of this syndrome with methotrexate is unusual; only nine cases have been reported in the literature. We describe the tenth case of this syndrome associated with methotrexate, which is also the third case of the bullous variant of methotrexate-induced acral erythema. Our case is unusual in that the acral erythema was present only on the soles of the feet and in that it was associated with the presence of diffuse maculopapular lesions over the legs and trunk.     

Exploring soft matter: liposomal vesicles and their tethers

The malleability of soft matter such as vesicular systems, allows their mechanical manipulation into various interesting structures. Their inherent elastic membrane properties can be utilized in fabricating micro-scaled transport machineries. In this paper, we have described several features of research carried out in our laboratory. This includes the self-healing ability of multilamellar liposome on removal of their inner core. The formation of tethers from their outer bilayers into complex networks has been demonstrated. Photo enhancement of images has revealed the apparent existence of narrow channels inside such tethers. The tethers channels were subsequently used as transport conduits to carry solid polystyrene microspheres as well as large liposomes larger than the tether diameter under controllable speeds of up to 2 microm s(- 1). The possibility of producing multi-compartment liposomal systems connected to each other directly by fusion or indirectly via tether networks has provided us with a system capable of transporting components from one vesicle entity to another.     

Transplantation activities in Iran

Iran is a tropical country with a land area of 1,648,000 square kilometers and a population of 68,100,000. Iran has a recorded history that dates back 2553 years. Its earliest medical school was Pasargad. Jondi Chapour University was founded 1753 years ago during the Sassanid dynasty as a center for higher education in medicine, philosophy, and pharmacology. Indeed, the idea of xenotransplantation dates back to days of Achaemenidae (Achaemenian dynasty), as evidenced by engravings of many mythologic chimeras still present in Persepolis. Avicenna (980-1037 AD), the great Iranian physician, performed the first nerve repair. Transplantation progress in Iran follows roughly the same pattern as that of the rest of the world, with some 10-20 years' delay. Modern organ transplantation dates back to 1935, when the first cornea transplant was performed at Farabi Hospital in Tehran, Iran. The first living-related kidney transplantation performed at Shiraz University Hospital dates back to 1968. The first bone marrow transplant was performed at Dr. Shariaati's Hospital in Tehran. The first heart transplant was performed 1993 in Tabriz, Iran. The first liver transplant was performed in 1993 in Shiraz. The first lung transplant was performed in 2001, and the first heart and lung transplants were performed in 2002, both at Tehran. In late 1985, the renal transplantation program was officially started in a major university hospital in Tehran and was poised to carry out 2 to 4 transplantations each week. Soon, another large center initiated a similar program. Both of these centers accepted surgical, medical, and nursing teams from other academic medical centers for training in kidney transplantation. Since 2002, Iran has grown to include 23 active renal, 68 cornea, 2 liver, 4 heart, 2 lung, and 2 bone marrow transplantation centers in different cities. In June 2000, the Organ Transplantation Brain Death Act was approved by the Parliament, followed by the establishment of the Iranian Network for Transplantation Organ Procurement. This act helped to expand heart, lung, and liver transplantation programs. By 2003, Iran had performed 131 liver, 77 heart, 7 lung, 211 bone marrow, 20,581 cornea, and 16,859 liver tranplantations. Sources of these donations were living-unrelated donor, 82%; cadaver, 10%; and living-related donor, 8%. The 3-year renal transplant patient survival rate was 92.9%, and the 40-month graft survival rate was 85.9%. Another large step in expanding the transplantation program is the construction of the Avi- Cenna (Abou Ali Sina) Transplant Hospital in Shiraz. This hospital hopefully will begin operation in 2 years. It will offer the opportunity for the exchange and sharing of organs and increased cooperation between transplant teams in the Middle East. The hospital offers great promise for transplant medicine in Iran and other Persian Gulf countries.