Secondary Sterilization Research Articles

Design of an intelligent Near-Infrared responsive antibacterial Nano-Platform based on MoS2/Cu3Mo2O9

In this era of high drug resistance, there is an urgent need for novel antimicrobial agents and strategies to achieve smarter sterilization effects. However, developing an environmentally friendly, controllable, and self-cleaning smart antimicrobial material remains a formidable challenge. In this work, a smart antimicrobial nanoplatform composed of Cu3Mo2O9 and MoS2 has been successfully designed and synthesized. The computational findings reveal that, owing to the interfacial coupling between the two substances at the solid junction, this architecture can effectively absorb near-infrared light, significantly reduce migration resistance, and improve carrier separation efficiency. Empirical observations demonstrate that with a sample concentration of 100 μg/mL, under near-infrared (NIR) laser irradiation, the microenvironmental temperature proximal to the bacteria can be swiftly elevated from 28.6 °C to in excess of 50 °C within a mere 6 min. The overall photothermal conversion efficiency is 32.6 %, and it exhibits an active oxygen level nearly 5 times higher than that of Cu3Mo2O9. Furthermore, the permeability of the cell membrane was greatly improved with the increased temperature, which is beneficial for the generated reactive oxygen species (ROS) entering the bacterial cells. After synergistic antimicrobial treatment, the antibacterial rate against Escherichia coli can reach over 99 %. More importantly, this nano-platform features a unique ’activation’ mechanism that uses NIR as an ’activation switch’ to selectively toggle between ’passive defense,’ ’secondary sterilization,’ and ’active attack’ antibacterial modes as needed. Upon interaction with aqueous environments, its reusability and favorable biocompatibility with terrestrial and aquatic life promise to facilitate the intelligent eradication of deleterious microorganisms in aquatic systems via the diurnal cycle of sunrise and sunset. This is highly significant for the ongoing management and maintenance of public resources such as amusement parks, artificial fish ponds, and urban water features.

Antibacterial mechanism of biogenic calcium oxide and antibacterial activity of calcium oxide/polypropylene composites

In this study, biogenic calcium oxide (CaO) was developed as a natural antibacterial agent. After the thermal treatment of waste scallop shell powder, a CaO antibacterial agent was obtained. In addition, the crystal phase and morphology of the calcined product were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial mechanism indicated that the alkaline environment caused by CaO hydration plays a vital role in the antibacterial action, in addition to the secondary sterilization of reactive oxygen species (ROS) by ·OH. CaO/polypropylene (PP) composites were prepared to examine the effectiveness of CaO as a bactericidal agent. Results revealed that the addition of CaO enhances the antibacterial activity of the composites and renders low toxicity. Such an eco-friendly natural inorganic antibacterial material demonstrates potential application prospects for sterilization.

3D/2D TMSs/TiO2 nanofibers heterojunctions for photodynamic-photothermal and oxidase-like synergistic antibacterial therapy co-driven by VIS and NIR biowindows

With the increasingly serious problem of antimicrobial resistance and the lack of clinical response strategies, the development of new antibacterial materials is imminent. Herein, a VIS/NIR co-irradiation photodynamic-photothermal and oxidase-like synergistic antibacterial platform of transition metal sulfide/TiO 2 nanofibers (TMSs/TiO 2 NFs) is proposed to fight bacterial infection. On one hand, three-dimensional (3D) MoS 2 nanoflowers load can quickly capture the photogenerated electrons of two-dimensional (2D) TiO 2 nanofibers, inhibit the recombination of electron-hole pairs and greatly increase the yield of reactive oxygen species (ROS), thereby overcoming the UV sterilization defects of pure TiO 2 , endowing TiO 2 excellent photodynamic antibacterial ability in the long-wavelength region. On other hand, with the combination of MoS 2 and TiO 2 , the photothermal effect of the 3D/2D heterostructure (MoS 2 /TiO 2 NFs) was significantly enhanced and the local temperature rose to above 50 °C in a short time, which was enough to induce the inactivation of bacterial protein, thereby providing an efficient secondary sterilization effect. In addition, MoS 2 /TiO 2 NFs has fascinating oxidase-like activity, which further accelerated the oxidation of physiologically relevant antioxidants in bacteria. In the end, MoS 2 /TiO 2 NFs exerted outstanding antibacterial efficiencies against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) through the synergy of photodynamic-photothermal and oxidase-like performance. Meanwhile, MoS 2 /TiO 2 NFs antibacterial platform effectively accelerated the healing of S. aureus -infected wounds and showed negligible toxicity and hemolysis on normal cells and tissues. Hence, this study contributed an effective alternative strategy for reducing the use of antibiotics, providing new ideas for application of semiconductor nanomaterials in collaborative combination therapy. • The 3D/2D TMSs/TiO 2 NFs (MoS 2 /TiO 2 NFs) heterojunctions are successfully prepared in situ. • MoS 2 /TiO 2 NFs heterojunctions are demonstrated to increases the yield of ROS. • MoS 2 /TiO 2 NFs show enhanced photodynamic-photothermal and oxidase-like properties. • MoS 2 /TiO 2 NFs process charming sterilization activity. • MoS 2 /TiO 2 NFs antibacterial agent accelerate S. aureus- infected wound healing.

The contamination of allografts in multi-organ donors: a bone bank experience.

As a consequence of the preference for homologous tissues, bone banks are the primary source of bone and tendon grafts. However, the bacterial, viral, and fungal contamination of these grafts remains a considerable challenge in bone banks and often results in high rates of graft discarding and infections in patients. This study intended to investigate bacterial contamination in 509 bone grafts harvested from 110 multiorgan donors. Specimen collection included bone and soft tissue retrieved from culture-swabbing as well as bone and capsule for histopathology. Microbiological, histopathological, and radiographic analyses were carried out. Secondary sterilization was also conducted using cobalt 60 at the dose of 2.5 × 104Gy. There were 106 multi-organ donors. Of the 506 grafts, there were 54 Hemi pelvis, 191 femur, 142 tibia, and 119 fibulae. The surface swab contamination rate for all the grafts retrieved was 16.6%, and bone culture from all the grafts was 6.1%. When we looked at the incidence of contamination according to the location than the surface swab contamination rate for hemipelvis was 18 (33.3%), femur 30 (15.7%), tibia 21(14.7%) and fibula 15 (12.6%). The bone cultures were hemipelvis 12 (22.2%) femur 8 (4.1%), tibia 5 (3.5%) and fibula 6 (5.04%). These findings suggest that separate harvesting of the grafts in reverse order may help prevent contamination. The study also recommends discarding all grafts contaminated even with low pathogenicity organisms. However, bioburden needs to be further investigated to be detected and reduced.

Perfection of the Technology for Production of Canned Apple Compotes Using Secondary Resources and Intensive Sterilization Regimes

This paper presents the results of research on improving the technology for production of canned apple compotes using secondary products after cutting and cleaning fruit for syrup boiling and intensive heat sterilization based on the use of new techniques—preliminary heating of fruit in cans in the ultrahigh frequency electromagnetic field with sterilization under intensive regimes with the use of high-temperature heat carriers and rotation of the cans during sterilization. It is established that the use of the resulting infusion of secondary products for syrup boiling provides saving of more than 8 kg of sugar per tube of product. In this case, the content of vitamin C in the finished product is more than two times higher than in the case of using the traditional method of blanching in hot water. Studies on the heating and actual lethality of microorganisms have shown that the developed mode provides the industrial sterility of canned food, saves heat energy, and shortens the duration of the heat sterilization mode by 20 min.

Perfection of production technology canned composites from apples using secondary resources and intensive sterilization regimes

Perfection of production technology canned composites from apples using secondary resources and intensive sterilization regimes

Creation of the bone bank of the Rabat and Casablanca region in Morocco.

For a long time the use of bone grafting has demonstrated its interest in orthopedic surgery and traumatology. The autografts which are still very frequently used present various problems. On the one hand, it is necessary to find a correct mechanical quality and a sufficient quantity of bone. On the other hand, the graft removal lengthens the operative time and generally painful in postoperative. These disadvantages of autografts have led to the development of bone allografts. Indeed, the low immunogenic power of the bone, the good integration of the graft and the ease of bone preservation techniques make it possible to overcome the various problems posed by bone autografts. The increasing use of bone allografts has resulted in the need for a structure allowing the management of graft stocks. The purpose of this work is to demonstrate the mode of operation of a bone bank, whose conservation activity is limited to the femoral heads treated by cryopreservation and without secondary sterilization process. The bank collaborates with all orthopedic surgeons in the Rabat and Casablanca city at first and then with all orthopedic surgeons in Morocco. It provides allografts in quality and safety.

Is Gamma Irradiation as a Secondary Sterilization Procedure Required for Decellularized Xenogenic Tissue Material?

Biological tissues for clinical use typically require gamma irradiation to achieve targeted sterility assurance level (SAL). Gamma radiation produces deleterious changes to physical and surface properties of tissues. In this study, we evaluate the requirement of gamma irradiation as a secondary sterilization procedure by comparing it with non-irradiated chemically treated xenograft tissues. Sixty four bovine pericardia (BP) were decellularized and subjected to nonconventional (glutaraldehyde free) cross-linking. Xenograft samples were screened for bacterial and fungal contaminations both at pre- and post-processing stages, after cross-linking and preservation. Microbial evaluations performed revealed that the xenografts were rendered 'microbe free' by subjecting to a new multistaged decellularization technique and cross-linking. Five of these cross-linked tissues were subjected to gamma irradiation as recommended by IAEC and were tested for surface and mechanical properties to understand the ultrastructure, surface and bulk properties. Surface tension and thrombogenicity parameters were also evaluated. Gamma-irradiated specimen showed reduced physical and mechanical properties of these xenogenic tissues significantly along with biological property. Validation and analysis led us to conclude that this microbe-free decellularization method and subsequent processing for xenogenic tissues is a viable alternative for clinical usage without the deleterious secondary sterilization using gamma irradiation.

Lateral position one-stage combined posteroanterior approaches for the treatment of lumbosacral tuberculous spondylitis

To investigate the feasibility of a one-stage combined posteroanterior approaches for the treatment of lumbosacral tuberculous spondylitis with the patients lying in a lateral position. A retrospective review was conducted for 15 patients with lumbosacral tuberculosis undergoing one-stage combined posteroanterior approaches for radical lesion resection and reconstruction. All patients were observed and evaluated by clinical and imaging studies. Operative posture:11 cases for right side and 4 cases for left side. The mean operative duration was 280 min (range: 230 - 380 min) and the mean estimated volume of blood loss 1720 ml (range: 1100 - 3000 ml). Imaging results: No recurrence of tuberculose focus was found until the last follow-up. Upon image reviewing, it showed no loosening or displacement except for two cases of slightly collapsed titanium mesh. Preoperative and postoperative changes in the degree of lumbar lordosis were statistically significant [(20 ± 5)° vs (31 ± 5)°, P < 0.05]. The Kirkaldy-Willis classification rating yielded satisfactory results for 13 cases. The patients with lumbosacral tuberculosis undergoing one-stage combined posteroanterior approaches may achieve radical lesion resection, posteroanterior collaboration and reconstruction. It avoids a 2-stage operation, eliminates the need of changing a patient's body position with secondary sterilization and shortens the operative duration. Lumbosacral surgery for tuberculosis combines the respective advantages of anterior, posterior and combined posteroanterior approaches and yet makes up for their deficiencies.

One-Stage Combined Posterior and Anterior Approaches for Excising Thoracolumbar and Lumbar Tumors

Retrospective clinical and radiologic evaluation. To investigate the feasibility of a 1-stage combined posterior and anterior approaches for excising thoracolumbar and lumbar tumors with the patient lying in the lateral position. Traditional anteroposterior approaches for total spondylectomy require a 2-stage operation or changing the patient's position, with secondary sterilization in the one stage. So the surgical time, cost and trauma, as well as blood loss, would be increased. One-stage en bloc spondylectomy with the patient lying in the lateral position may be a good way for improving it. This study retrospectively reviewed 18 patients with thoracolumbar and lumbar spinal tumors who underwent spondylectomy. All patients were observed up, and their status was evaluated by clinical and imaging studies. Total en bloc spondylectomy was performed successfully in 15 patients, and 3 patients underwent bulk vertebrectomy. All patients were observed up for 18 months to 3 years (mean, 2 years). Posterior pedicle screw fixation and anterior intervertebral titanium mesh placement were stable in all patients, with satisfactory positions. Two patients with preoperative neurologic deficits recovered less than 3 weeks after surgery. One patient with thyroid metastasis underwent artificial joint replacement 5 months after surgery. Two patients with metastatic tumor died 6 months and 8 months, respectively, after surgery. Ten months after surgery, local tumor recurred in one patient with chondrosarcoma. One patient with Ewing's sarcoma died due to distal metastasis 1 year after surgery. The 1-stage combined posterior and anterior approaches with the patient lying in the lateral position, used to excise thoracolumbar and lumbar spinal tumors, is feasible and permits sufficient exposure, reduces the risk of neurovascular injury and blood loss during surgery, facilitates total en bloc spondylectomy and spinal reconstruction, and reduces the surgical time of a 2-stage procedure and repositioning the patient. This method can be used effectively for excising spinal tumors.

A Systematic Review of Anterior Cruciate Ligament Reconstruction with Autograft Compared with Allograft

Anterior cruciate ligament reconstruction can be performed with use of either autograft or allograft tissue. It is currently unclear if the outcomes of these two methods differ significantly. This systematic review and meta-analysis investigated whether the short-term clinical outcomes of anterior cruciate reconstruction with allograft were significantly different from those with autograft. A computerized search of the electronic databases MEDLINE and EMBASE was conducted. Only therapeutic studies with a prospective or retrospective comparative design were considered for inclusion in the present investigation. Two reviewers independently assessed the methodological quality and extracted relevant data from each included study. If a study failed the qualitative assessment and statistical tests of homogeneity, it was excluded from the meta-analysis. Furthermore, a study was withdrawn from the meta-analysis of a particular outcome if that outcome was not studied or was not reported adequately. A Mantel-Haenszel analysis utilizing a random-effects model allowed for pooling of results according to graft source while accounting for the number of subjects in individual studies. Nine studies were determined to be appropriate for the systematic review. Eight studies compared bone-patellar tendon-bone grafts, and one study compared quadruple-stranded hamstring grafts. Five studies were prospective comparative studies, and four were retrospective comparative studies. One study, which investigated allografts that underwent a unique sterilization process, demonstrated an allograft failure rate of 45% (thirty-eight of eighty-five). That study failed the qualitative assessment and statistical tests of homogeneity and consequently was excluded from the meta-analysis. When the outcomes from the remaining studies were pooled according to graft source, the meta-analyses of the Lysholm score, instrumented laxity measurements, and the clinical failure rate estimated mean differences and odds ratios that were not significant. These findings were robust during the sensitivity analysis, which varied the included studies or variables on the basis of graft type, instrumented laxity cut-off value, secondary sterilization technique, duration of follow-up, mean patient age, and study methodology. In general, the short-term clinical outcomes of anterior cruciate reconstruction with allograft were not significantly different from those with autograft. However, it is important to note that none of these nonrandomized studies stratified outcomes according to age or utilized multivariable modeling to mathematically control for age (or any other possible confounder, such as activity level, that is not equally distributed in the two treatment groups). Understanding these limitations of the best available evidence, the surgeon may incorporate the results of the present systematic review into the informed-consent and shared-decision-making process in order to individualize optimum patient care.

The Location in Cartilage of Infectious Retrovirus in Cats Infected with Feline Leukemia Virus

Background: Previous studies have suggested that articular cartilage allografts were not likely to transmit infectious retrovirus since viral DNA could not be isolated from chondrocytes of infected individuals. However, the ability of the extracellular matrix of articular cartilage to harbor and transmit a retrovirus has not been examined. We hypothesized that articular cartilage fragments, but not isolated chondrocytes, from cats systemically infected with feline leukemia virus (FeLV) are capable of transmitting infectious retrovirus. Methods: Fresh cartilage segments and chondrocytes isolated from cats systemically infected with feline leukemia virus were used in this study. Feline embryonic fibroblast cells were cocultured with segments of cartilage, isolated chondrocytes, or fragments of cortical bone from each infected cat. The FeLV p27 antigen was measured in the coculture media by enzyme-linked immunosorbent assay. In addition, FeLV proviral nucleic acids were quantified by real-time quantitative polymerase chain reaction with use of DNA extracted from feline embryonic fibroblast cell cocultures as well as isolated chondrocytes. Immunohistochemistry was used to assess for FeLV p27 antigen in both intact cartilage fragments and isolated chondrocytes. Results: Feline embryonic fibroblast cells cocultured with cartilage fragments from each of the five FeLV-infected cats all demonstrated high levels of proviral DNA, indicating transmission of infective virus. In addition, media from all cocultures of feline embryonic fibroblast cells and chondral fragments became positive for p27 antigen, indicating active viral replication. In contrast, cocultures of feline embryonic fibroblast cells and isolated chondrocytes from all FeLV-infected cats were negative for proviral DNA and p27 antigen. Likewise, no proviral nucleic acids could be detected in isolated chondrocytes from any infected cats. Cocultures of feline embryonic fibroblast cells with cortical bone fragments were positive for proviral DNA and p27 antigen. Immunohistochemical staining of cartilage fragments from FeLV-infected cats demonstrated the presence of p27 antigen throughout the extracellular matrix, but the p27 antigen was not detected in isolated chondrocytes. Conclusions: Articular cartilage fragments can readily transmit infectious retrovirus, but isolated chondrocytes were likely not the source of the infectious virus because they did not harbor proviral DNA or p27 antigen. Clinical Relevance: Because donor-cell viability improves the long-term function of chondral allografts (precluding the use of secondary sterilization procedures employed for tendon and bone allografts), these results underscore the importance of rigorous donor screening when the use of articular cartilage allografts is being considered.

Allografts in Sports Medicine

Society has long recognized the medical importance of donating and transplanting organs and tissues. Allografts are used routinely for sports medicine applications and in a large variety of other non-sports related surgical procedures. Allogeneic tissue research has been influenced by the increase in demand for transplantable grafts for both non-sport and sport related surgeries. Disease transmission prevention is a key factor in the proliferation and success of the allografts used today. Disease transmission prevention methods are accomplished by social screening, serology, and various types of secondary sterilization. These methods are increasingly assessed and regulated by the FDA, the American Association of Tissue Banks and their accredited member organization tissue banks. Sports medicine surgeons initially used allografts to augment their autograft use when autologous sources were not available. While the number of grafts and types continue to grow, demand continues to increase as well. Some allografts undergo minimal processing and only require minor preparation prior to use, however other procedures require grafts that are sized dimensionally and matched for their recipients. Our continuing experience with a variety of allograft types has led us to conclude that allograft use is a legitimate primary or alternate source in the ligamentous or cartilage reconstruction or transplant in sports medicine. Cost and availability will always limit allograft usage; however concerns regarding inferior clinical results should not. Our experience and those reported by others, indicates that comparable clinical results can be obtained with the added benefit of reduced surgical morbidity by the use of allografts.

Effect of gas-plasma sterilization on the osteoinductive capacity of demineralized bone matrix.

The current study evaluated the effect of low-temperature hydrogen peroxide gas plasma sterilization on the osteoinductive capability of human demineralized bone matrix using a rat model. Twelve athymic rats received three separate implants consisting of steam-sterilized demineralized bone matrix (negative control), sterile-harvest demineralized bone matrix (positive control), and gas-plasma-sterilized demineralized bone matrix. A demineralized bone matrix pellet from each sterilization group was placed individually into one of three separate soft tissue pockets created in the epaxial musculature of each rat. All 12 rats were euthanized 9 weeks after implantation. Each implantation site was removed along with 0.5-cm normal tissue around the implant. Histologic examination was done on each implant site to determine the presence or absence of new bone, cartilage, or bone marrow elements. All 12 sterile harvest demineralized bone matrix sites histologically contained new bone elements, whereas none of the negative control or gas plasma sterilized demineralized bone matrix sites contained any of these same elements. The results of this study indicate that demineralized bone matrix sterilized with low-temperature, gas-plasma sterilization loses its osteoinductive capacity in a manner similar to that of steam-sterilized demineralized bone matrix, making low-temperature, gas- plasma sterilization unsuitable as a method of secondary sterilization of demineralized bone matrix.

Bone allograft contamination in multiorgan and tissue donors.

Multiorgan and tissue donors offer a larger quantity and high quality of bone allograft that cannot be obtained from living donors. The risk of bone contamination must be borne in mind if secondary sterilization is not performed. The bacteriological cultures of 270 bone segments obtained from 53 multiorgan or tissue donors were analysed to study the relationship between previous organ and tissue procurements and bone retrieval contamination. We concluded that no significant differences in bacterial contamination percentage were found for each type of previous organ and tissue procurement, nor in the number of teams per donor.

A possible process of the secondary sterilization: delayed anovulation syndrome.

Die Wirkung verschiedener Testosterondosen auf die postpuberale Ovulation von Ratten wurde untersucht, wobei an Ovarien der Nachweis gelang, dass der anovulatorische Zustand nach der Pubertat testosteron-dosisabhangig ist.