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Steam sterilization practices, standards, and products in the United States are changing as the U.S. health care system continues to undergo dramatic restructuring. The causes of this restructuring are hospital consolidations, implementation of diagnostic-related-group reimbursement, cost-containment programs, and increasing acceptance of disposable packs.
Trash-to-stem incineration systems were seen in the late 1970s as one solution to the energy crisis. A decade later, they are being viewed as a response to the rapidly growing waste disposal crisis. However, in the interim, public fears of pollution from these systems have stemmed their popularity. Hospitals, which are confronted with the need for efficient and cost-effective methods of trash handling, must determine whether these fears are valid and, if they are not, learn how to combat them to allow trash-to-steam incineration systems a role in overall waste management strategies.
Steam-sterilizable membrane probes for monitoring the dissolved oxygen level in fermentors, or the oxygen content of gas streams, are described. The probes have a silver cathode, a lead anode, and an acetate buffer as an electrolyte. The membrane is Teflon. The current output of the probes in the absence of oxygen is negligible.
The design of the steam-jacketed sterilizer includes an exterior air-gap fixture through which purged chamber aerosols potentially could escape into the ambient environment. Studies of the purge cycle in two sterilizer models tested the potential release of a genetically marked Enterococcus faecalis, together with Bacillus stearothermophilus spores introduced as exposed cultures. Direct plate counts, broth enrichment and polymerase chain reaction analysis were used to confirm any released organisms trapped in an all-glass impinger. From the retrieval of both bacterial strains, an estimated 10(3) organisms can be released from uncontained bacterial loads of 10(11) E. faecalis and 10(7) B. stearothermophilus, even from properly functioning autoclaves. The release of an opportunistic pathogen from sterilizer purge exhausts emphasises the importance of proper sterilizer location, ventilation, containment of heavily contaminated loads, and adequate sterilizer maintenance.
In order to reduce the total enzyme consumption in high-solids static hydrolysis of nonwashed steam-exploded willow Salix caprea by mixed cellulase of Trichoderma reesei + Aspergillus foetidus, two different approaches were proposed. In the first case, the enzyme activity adsorbed on residual solids after extended hydrolysis was used for hydrolysis of the newly added substrate. The initial mixing of fresh and hydrolyzed substrates was sufficient for the adsorbed enzyme redistribution and conversion of the new substrate portion, and permanent mechanical stirring was not required. Feeding of two additional portions of the exploded hardwood adjusted to pH 4 with dry caustic into the reactor with simultaneous replacement of accumulated sugars with fresh buffer (pH 4.5) resulted, on average, in a 90% conversion of cellulose at the final enzyme loading 8 IFPU per g ODM substrate, an average sugar concentration of 12%, and a glucose/xylose ratio of 5:1. In the second approach, weakly adsorbed cellulase fractions were used for static high-solids hydrolysis followed by their ultrafiltration recovery from the resultant sugar syrup. In contrast to the initial cellulase mixture whose residual activity in a syrup did not exceed 5-10% at the end of hydrolysis (48 h), up to 60% of weakly adsorbed enzyme fraction could be separated from sugar syrups by ultrafiltration and then reused. Weakly adsorbed enzymes displayed a hydrolysis efficiency of not less than 80% per IFPU enzyme consumed in extended hydrolysis of pretreated willow as compared to the original enzyme mixture. An electrophoretic study of the weakly adsorbed enzyme fraction identified T. reesei cellobiohydrolase II as the predominant component, whereas clear domination of T. reesei cellobiohydrolase I was found by electrophoresis of proteins tightly bound to hydrolysis residual solids.
This study intended to verify, through microbiological techniques and TEM investigations, the killing of bacterial spores after treatment in steam autoclave, and to propose strictly morphological considerations about the target of this sterilisation process. Autoclave is the most common device for sterilising instruments in order to prevent cross infections in dental offices. The autoclave efficiency has been improved in the last years and part of this improvement is related to both a better and more correct use of the autoclave system and to the technological innovations introduced in the last generation of devices. However, associations as ADA or CDC suggest to regularly verify the process of 'autoclaving' through biological indicators (BI). The most commonly used BI are made of spores strips or suspensions of Bacillus Subtilis (pb 168) and Bacillus Stearothermophilus (ATCC 10149). They visually prove, changing colours on enzymatic base, the death of micro-organism and if the physical parameters, necessary for sterilisation, have been achieved. These two strains of endospore-forming bacteria were processed and prepared following two different techniques: Karnovsky fixed and epon embedded--phosphotungstic acid fixed for direct observation. The kind and the extent of analysed modifications are extremely various: from deep lacerations, which changed the spore structure, to little clefts which let the cytoplasm go out.
The purpose of this study was to evaluate the killing effect that treatment in gravity or high-vacuum steam autoclaves had on endospores present on strips or applied to dental needles within 10 types of small sharps containers. Spore strips containing Bacillus stearothermophilus endospores were used, while needles were soiled with an equal number of spores or with spores mixed with blood. Needles were tested capped and uncapped. Strips and needles were autoclaved in empty and 3/4 filled containers placed in several orientations (vents open or closed, upward or on-side). If sterilization was not accomplished within the initial period, additional exposure time was added up to a one hour maximum. Major findings for gravity autoclaves were: 1) strips and needles present in empty containers could, in most cases, be sterilized within 15 minutes when the vents were left open and the containers were placed on-side; 2) spore- and spore plus blood-soiled needles were more difficult to sterilize then were commercial spore strips; 3) capping of needles and the presence of blood did not decrease sterilization efficiency; 4) sterilization in the presence of fill material required additional exposure times and 5) larger containers (greater than 500 ml volume) were more difficult to sterilize than were the smaller (250 ml) ones. All type of open-vented, filled containers could be sterilized within 10 minutes in a high-vacuum autoclave.
In the wood-to-ethanol process, pretreatment of the material is necessary prior to enzymatic hydrolysis to obtain high overall yields of sugar and ethanol. Steam pretreatment of fast-growing Salix either with or without SO2 impregnation has been investigated by varying different parameters. Overall glucose yields of above 90% and overall xylose yields higher than 80% were obtained both with and without impregnation. However, the most favorable pretreatment conditions for the separate yields of glucose and xylose differed to a lower degree using SO2-impregnated wood chips, resulting in higher total sugar yield than that obtained with non-impregnated wood chips.
An ultrafiltration membrane bioreactor consisted of 1 - 6 enzymatic vessel was used to increase the reducing sugar concentration. The effects of enzyme loading, the number of enzymatic vessel and the dilution rate on enzymatic hydrolysis of steam-exploded rice straw were studied. The results show that the best condition is: 20FPU/g, four enzymatic vessels and 0.075/h (D). Compared with traditional batch reaction, the conversion of substrate increased significantly from 18% - 21% to 39.5%. Compared with the ultrafiltration membrane bioreactor consisted of one enzymatic vessel, the production of reducing sugar increased from 0.25 g/ g to 0.4g/g, and the final reducing sugar concentration in the product stream increased from 4.56g/L to 27.23g/L.
The article describes effects of unique thermal springs of Yangan-Tau mountain in patients with locomotor diseases. Effects of gas, steam and thermal factors of the water from the above springs were studied in patients with rheumatoid arthritis who took baths in the sanatorium Yangan-Tau. Changes in the cytokine profile of the patients were analysed.
The use of methyl methacrylates for cranial repairs has been well established. Procedures for sterilization of these materials include soaking in benzalkonium chloride, use of ethylene oxide gas, or cobalt 60 irradiation. Although ethylene oxide sterilization is the most common method, gas sterilization and degassing of these prefabricated implants may require almost as much time as fabrication. This study evaluated impact strength and linear dimensional change following steam autoclave sterilization of heat-processed methyl methacrylate. It was compared to an autopolymerizing methyl methacrylate for impact strength. No statistical difference was found in impact strength between nonsterile heat-processed methyl methacrylate and autoclaved heat-processed methyl methacrylate; however, both were significantly stronger than the autopolymerizing material. A statistically significant linear dimensional change of 1.211% between the autoclaved and nonsterile heat-processed methyl methacrylate was found, but was not considered clinically significant.
The effectiveness of steam autoclaving on bacterial endospores placed within five types of sharps containers was tested. A variety of container physical orientations within the autoclave were evaluated. Spores were present on commercial spore strips or placed onto capped and uncapped dental needles. All strips and needles present in empty or filled containers could be sterilized within 15 minutes when the containers were placed on their sides and their vents left open. The contents of containers processed in an upward position required between 30-60 minutes of autoclaving before being sterilized. The size and shape of the containers influenced ease of sterilization.
Success of endodontic therapy depends upon both operator's skill and quality of the employed instruments. K-files have been examined for they probably are the most commonly used endodontic instruments. It is particularly important to take into consideration, together with the original quality of the instruments, its possible changes due to the wear from sterilization. In this paper have been therefore evaluated the characteristics of brand-new K-files from three different manufacturers together with the wear of the same instruments after paraformaldehyde steam sterilization.
Steam sterilization-in-place (more commonly known by its acronym as SIP) is coming into wider usage within the pharmaceutical and biotechnology industries as firms endeavor to increase the level of sterility assurance associated with those products made by aseptic processing. Despite this increase in interest, sterilization-in-place has not been given the attention its growing importance appears to warrant. The intent of this presentation is to define the overall concepts involved with the application of SIP technology and review how these concerns affect specific systems.
The dependence is derived to determine the duration of drying process for medical products in the course of steam sterilization. The drying index for assessing efficiency of different drying techniques is proposed. With the index, the most useful drying technique can be selected, and the duration of drying process can be determined.
Through a study at 10 hospitals located throughout the United States, a method for determining the costs of operating steam sterilization equipment was devised and tested. Any hospital central sterile supply manager can use this method to monitor his sterilizers' cost per hour of operation and cost per load.
The level and variability of nonspecific microflora of steamed sausage was determined in the course of its production. The microbiological characteristics was based on determinations of 11 groups of microorganisms, taking into consideration three production phases, two different meat works and two seasons of the year as variation factors. A high contamination of the sausage meat, on average 10(6) microorganisms/g, was found just before putting it into tubes. These amounts were reduced in the course of technological processes, which averaged 10(4)/g in the product. Statistically significant variation of the quantitative level was found between the production phases in most of the microorganism groups studies, a significant influence of the individual meat works and seasons of the year being absent. Quantitative percentage of the particular microorganism groups in total contamination was determined. The correlations calculated for quantitative variability of the total bacterial contamination in relation to the individual microorganism groups were shown to be significant.
As a supplement to a preceding paper (Zbl. Hyg., 194 (1993). 369-279) the resistance of bioindicators has been investigated which differed only in the material of which the carriers are made (filter paper and glass fibre fleece, respectively). The conditions of the tests were such that further evidence could be expected for the fact that the characteristic values of bioindicators can be falsified by superheating of the carrier and its envelope. As a test organism Enterococcus faecium has been used. To avoid side effects, the bacteria have been dried on to the carriers from a suspension in water distillators. The exposition basket of the resistometer has been loaded with 3 rows of 15 indicators (disc shaped; diameter: 6 mm), arranged parallel. At a temperature of 68 degrees C the dependency of (relative) frequency of indicators having surviving test organisms capable of multiplying on exposure time to saturated steam has been determined. Free exposed indicators made of filter paper required considerably longer exposure periods than indicators made of glass fibre fleece to change from "(nearly) all the indicators have test organisms capable of multiplying" to "(nearly) all the indicators are free from test organisms capable of multiplying". The exposure time to free 50% of carriers made of filter paper from test organisms capable of multiplying (t50%) amounted to 44.1 minutes. The frequency of indicators free from test organisms was higher at the ends than in the middle of the exposed rows. When such indicators had been wetted before exposure, they showed a t50% value of 2.3 minutes, and the frequency of indicators free from surviving test organisms was distributed over the exposed indicators evenly. Free exposed indicators made of glass fibre fleece showed a t50% value of 4.4 minutes. The frequency of indicators free from test organisms was evenly distributed. Wetting of the indicators before exposure changed t50% value only slightly. When indicators made of glass fibre fleece had been exposed between two layers of filter paper they showed a very high t50% value (47.5 minutes), and the frequency of indicators free from test organisms was unevenly distributed. Indicators being sterile could be found mainly at the ends of the exposed rows. In an envelope of parchment paper bioindicators made of glass fibre fleece showed considerably higher characteristic values than when free exposed. Superheating of the carriers amounted to about 3 Kelvin.(ABSTRACT TRUNCATED AT 400 WORDS)