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PubMed1987

Observations on a formaldehyde low-temperature steam sterilizer.

In Finnish hospitals, heat labile equipment is mostly sterilized by ethylene oxide (EO) gas. Formaldehyde sterilizers are rarely used. We have tested a new commercial autoclave constructed exclusively for formaldehyde and low-temperature steam (F-LTS) sterilization, offering a potentially safer and cheaper method of sterilization. Both the sterilizing efficacy of the apparatus and the levels of formaldehyde in the processed materials were studied.

Equipment and Supplies, Hospital↗
PubMedDate not supplied

Induction of 1,2-dicarbonyl compounds, intermediates in the formation of advanced glycation end-products, during heat-sterilization of glucose-based peritoneal dialysis fluids.

OBJECTIVE: To study the presence of 1,2-dicarbonyl compounds in peritoneal dialysis (PD) fluids, their concentration in effluents with increasing dwell time, and their role in the formation of advanced glycation end-products (AGEs). MEASUREMENTS: Dicarbonyl compounds in heat- and filter-sterilized PD fluids were quantified by reverse-phase high performance liquid chromatography (HPLC) after derivatization to dimethoxyquinoxaline derivatives. Kinetics of the in vitro formation of AGEs upon incubation of 1,2-dicarbonyl compounds or PD fluids with albumin, with or without aminoguanidine, were measured by AGE fluorescence (excitation/emission wavelengths of 350 nm/430 nm). PATIENTS: AGEs and dicarbonyl compounds were measured in effluents collected from standardized 4-hour dwells from 8 continuous cycling peritoneal dialysis patients. RESULTS: In PD fluids, 3-deoxyglucosone (3-DG) has been identified as the major dicarbonyl compound formed during the process of heat sterilization. The process also formed glyoxal (GO) and methylglyoxal (MGO), with the amount of 3-DG being approximately 25-60 times higher than GO and MGO. When incubated with albumin, the identified 1,2-dicarbonyl compounds rapidly formed AGEs. The formation of AGEs was more pronounced in conventional heat-sterilized PD fluids compared with filter-sterilized PD fluids, and was completely inhibited by aminoguanidine. In effluents, the concentration of MGO, GO, and 3-DG decreased with increasing dwell time, with a concomitant increase in AGE fluorescence. CONCLUSIONS: The dicarbonyl compounds 3-DG, MGO, and GO are potent promoters of AGE formation. The presence of these and possibly other dicarbonyl compounds formed during heat sterilization of glucose-based PD fluids is, to a large extent, responsible for the in vitroAGE formation by these fluids, as evidenced by the speed of AGE formation in PD fluids and the complete inhibition by aminoguanidine. Because 3-DG, MGO, and GO are rapidly cleared from PD fluids during dialysis, these compounds may contribute to the in vivo AGE formation in PD patients.

Adult↗
PubMedDate not supplied

The application of response surface methodology to sterilization process development and validation of a water cascade autoclave.

The application of Response Surface Methodology (RSM) to the performance validation of a water cascade sterilizer is described. The methodology was successfully used to 1) identify the cold and hot zones within maximum load configurations through three dimensional thermal mapping, 2) demonstrate the consistency of consecutive sterilization cycles in companion sterilizers, and 3) set target sterilizing values (F0) to achieve a high statistical assurance that any location will be above a minimum F0 (sterility assurance) and below a maximum F0 (for stability considerations).

Hot Temperature↗
PubMed1999

Release of bacteria during the purge cycles of steam-jacketed sterilizers.

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.

Air Microbiology↗
PubMed2000

Economic and clinical outcomes of microlaparoscopic and standard laparoscopic sterilization. A comparison.

OBJECTIVE: To compare micro-laparoscopic surgical sterilization and standard laparoscopic sterilization with respect to cost effectiveness and patient preferences. STUDY DESIGN: A retrospective study of all laparoscopic surgical sterilizations performed under general anesthesia at Johns Hopkins Bayview Medical Center--16 micro-laparoscopies and 34 standard laparoscopies. Cases selected for review were limited to patients undergoing surgical contraception and not requiring additional, concurrent procedures. Laparoscopic surgical sterilization was performed using a double-puncture technique with silicone band application. In each case either a standard, 10-mm laparoscope or a 2-mm micro-laparoscope was used, and the procedure was performed under general anesthesia. Postoperative pain management was achieved by nonsteroidal antiinflammatory drugs and/or narcotic analgesia. All cases were performed by residents under faculty supervision. Medical records and hospital billing records were reviewed, and a standardized telephone interview was conducted to assess postoperative quality of life and patient satisfaction. RESULTS: Both techniques were comparable in cost effectiveness. There was no significant difference in operating room time, average operating room costs, average ancillary department costs, instrument and supply costs, or length of stay. Postoperative discomfort was significantly less with microlaparoscopy (P = .05), and patient satisfaction was higher in the microlaparoscopy group. CONCLUSION: Microlaparoscopy and the standard laparoscopic approach for surgical sterilization are associated with similar hospital charges. Postoperative pain and overall patient satisfaction were significantly better with microlaparoscopy than standard laparoscopy.

Arizona↗
PubMedDate not supplied

Evaluation of glutaraldehyde and povidone iodine for sterilization of wide-field contact vitrectomy lenses.

BACKGROUND AND OBJECTIVE: Wide-field vitrectomy contact lenses are currently sterilized with ethylene oxide gas, and other lenses with autoclaving. To maintain a large inventory or possibly run the risk of loss of lens quality with repeated autoclaving, glutaraldehyde 2% and povidone iodine 5% solution were evaluated as possible sterilizing agents. MATERIALS AND METHODS: Ethylene oxide presterilized lenses were contaminated with known concentrations (10(5) organisms/mL) of bacteria (S. epidemidis, P. aeruginosa, B. subtilis), and fungi (A. flavus, C. albicans) for 5 minutes. The test lenses were treated with glutaraldehyde or povidone iodine for 5, 10, 30, 60, and 120 minutes, and controls with sterilized water for a similar duration. Following treatment, both test and control lenses were sampled with sterile cotton swabs. The swabs were cultured for bacteria (tryptone soya broth 48 hours), and fungi (Saubourd's dextrose broth 5 days). RESULTS: The culture was negative for both glutaraldehyde- and povidone iodine-treated lenses against all organisms at all time points except B subtilis, which needed 120 minutes treatment. CONCLUSION: Two hours contact time with glutaraldehyde 2% or providone iodine 5% can sterilize vitrectomy contact lenses against common bacteria and fungi without affecting lens quality.

Bacteria↗
PubMedDate not supplied

Sterilization of a new medical device using broad-spectrum pulsed light.

In the development of implantable medical devices, effective sterilization is an essential design element. This article outlines how broad-spectrum pulsed light (BSPL) has been implemented to sterilize a novel, implantable medical device. Components of the device have properties incompatible with most sterilization techniques. The unique characteristics of the device and sterilization method are described. Results are presented that show BSPL can be an effective sterilization method that has the potential to meet validation requirements to allow parametric release of the treated product.

Equipment Contamination↗
PubMed1975

[Sterility control: basic mathematical considerations (author's transl)].

The subject of control of sterility in homogenous lots by means of random sampling is discussed. The probability that non-sterile lots may be declared as accepted, was calculated by means of hypergeometric, binomial, and Poisson distribution. The following factors were considered: size of samples, size of lots, and degree of contamination of lots. The values obtained were reproduced in graphs (Figs. 1, 2, and 4). Reference is made to the conditions that have to be met in each case to enable a use of the various distribution functions for a calculation of the acceptance probability of non-sterile lots (Table 1). Furthermore, the necessary size of samples to contain at least one contaminated unit was calculated by means of binomial distribution for probabilities of 90, 95, and 99% (Fig. 3). For example, from a lot having a degree of contamination of 10%, 30 units would have to be assayed for sterility to recognize non-sterility of such a lot in 95% of cases. A degree of contamination of 1% would reguire already 300 units to be examined...

Mathematics↗
PubMed2001

Lipid extracted freeze-dried bank bone sterilized with low temperature plasma.

Ethylene oxide gas (EOG) is widely used for sterilization of freeze-dried bone. Recently EOG is regulated for clinical use because of cytotoxicity and environmental pollution concerns. Low Temperature Plasma Sterilization (LTPS) has no toxicity and mutagenicity working with a hydrogen peroxide gas plasma at 45 degrees centigrade. We have now used this method experimentally and clinically to sterilize freeze-dried bone. Cortical bone with a thickness of 5 mm and cancellous bone with a 10 mm cubic size were prepared, washed, defatted, dehydrated by freeze drying and finally sterilized by LTPS. As a Microbiological test, defatted freeze-dried bone was contaminated with B. subtilis, and after then the contaminated bone was treated with LTPS and the bacteria was proven inactive. Mechanical testing on rabbit cortical bone was investigated by compression testing using a mechanical testing machine. No differences between EOG treated and LTPS treated bone were found. From December 1996, 52 patients who had small and middle bone defects were treated with defatted, freeze-dried and LTPS sterilized bone. Clinical result was good. No deep infections, no transmission of virus infections or severe graft absorption were noted. The LTPS bank bone is safe and useful to reconstruction to small bone defects.

Bone Banks↗
PubMed2002

Ovarian function and regulation of the hypothalamic-pituitary-ovarian axis after tubal sterilization.

OBJECTIVE: To assess the effects of laparoscopic tubal sterilization with Hulka or Filshie clip on ovarian function and regulation of the hypothalamic-pituitary-ovarian axis. STUDY DESIGN: Hormonal changes were evaluated in 33 women undergoing sterilization with Hulka (n = 16) or Filshie clips (n = 17). All participants were healthy, with regular menstrual cycles. The levels of estradiol, follicle-stimulating hormone, luteinizing hormone, sex hormone binding globulin, prolactin, testosterone and androstenedione were measured in one cycle immediately before and 3 and 12 months after sterilization on cycle days 3-7 and 20-24. Repeated measures analysis of variance, paired t test and nonparametric Friedman two-way analysis of variance were used for statistical analysis. RESULTS: The follicular phase estradiol values increased after sterilization. The highest values were observed three months after the procedure (204.8 +/- 119.1 pmol/L vs. 170.3 +/- 111.7 pmol/L) (P = .0407). The values declined to the presterilization level by 12 months (150.3 +/- 71.3 pmol/L). The luteal phase estradiol values did not change significantly. No change in any of the other hormones studied took place, with the exception of a slight increase in follicular phase luteinizing hormone levels (4.4 +/- 1.4 U/L in the first cycle, 5.1 +/- 1.3 U/L in the second cycle and 5.2 +/- 1.8 U/L in the third cycle) (P = .0553). CONCLUSION: Laparoscopic tubal sterilization increases follicular phase estradiol levels, but the change seems to be only temporary.

Adult↗
PubMed2002

[Tests of the microbiologic barrier in sterile packaging].

After decontamination, cleaning, maintenance and functional testing, sterilised items must be packed suitably. The package must protect sterilised items against microbial contamination during removal from the sterilising chamber, and during storage or transport until use. The ability of any given pack to withstand penetration by bacteria is termed bacterial barrier efficiency. The assurance to keep the contents of the packaging sterile is determined by quality of the materials and the quality of seals. The research was done to proof the microbial barrier, determined by quality of the packaging materials/systems used to sterilization in hospital practice in Poland. 4 packaging materials and 4 types of containers were tested. In all used methods the growth of microorganisms indicated the lack of the bacterial efficiency, the lack of growth--the bacterial barrier efficiency. It was proved that two tested specialistic sterilization papers, non woven material and specialistic containers (metal with a filter or valve, plastic with a filter) are effective microbial barriers because it was no microorganisms growth. It has been determined that sulphite bleachery paper of 60 g/m2 and Schimmelbusch container do not provide the microbial barrier. Based on the performed studies it has been determined that sulphite bleachery paper and Schimmelbusch container can not be used as sterilization packaging system in sterilization practice in hospitals.

Bacteria↗
PubMed2003

[Mechanical properties of nickel-titanium files following multiple heat sterilizations].

AIM: The effect of cycles of sterilization procedures on nickel-titanium (NiTi) endodontic instruments is a serious concern for practitioners. There is no agreement in the literature whether these procedures could adversely affect the mechanical properties of endodontic files, and, consequently, increase the risk of intracanal failure. The purpose of this study was to evaluate the mechanichal resistance of Hero (MicroMega, Besancon, France) instruments, before and after sterilization procedures. METHODS: Thirty 02, 04, 06 tapered Hero size 30 new instruments were chosen and divided into 3 groups. Group A (control) were tested according to ANSI/ADA Spec.no 28 for torsional resistance, angle of torque and angle at breakage (45 inverted exclamation mark ). Group B files were first sterilized with chemiclave for 10 cycles of 20 minutes at 124 inverted exclamation mark C and then tested as described above. Group C files were first sterilized with glass beads for 10 cycles of 20 sec. at 250 inverted exclamation mark C and then tested as described above. Data were collected and statistically analyzed (t-paired test). Differences among the 3 groups were statistically not significant for both tests. RESULTS: All data were well within Spec.no 28 standard values. CONCLUSION: From the results of the present study, we may conclude that repeated sterilization procedures do not adversely affect the mechanichal resistance of Hero files.

Dental Implantation, Endosseous, Endodontic↗
PubMed1992

Influence of sterilization, drying and oat bran enrichment of pasta on glucose and insulin responses in healthy subjects and on the rate and extent of in vitro starch digestion.

The effects of sterilization and oat bran enrichment of pasta on the glucose and insulin responses in healthy subjects were evaluated. Cooked and canned spaghetti and cooked fettucini without and with enrichment with oat bran (28%) were compared. Further, the effects of various low- and high-temperature drying conditions for spaghetti, cooking time and sterilization on the starch digestion rate and content of enzyme-resistant starch (RS) in vitro were also studied. Various cooking quality data were also determined to allow interpretation of results. The incremental glucose area (0-120 min) produced by canned spaghetti was twice the area of that produced by cooked spaghetti (69.03 vs 35.45 mmol/l x min, P less than 0.01). The incremental insulin area (0-120 min) was also significantly higher with canned spaghetti (17,500 vs 12,600 pmol/l x min, P less than 0.05). The rapid digestion was caused by excessive swelling of starch during sterilization that promoted a very soft texture of the spaghetti. Enrichment of fettucini with oat bran reduced slightly the incremental insulin area (15,600 vs 20,100 pmol/l x min, P less than 0.05, for 0-120 min), but did not significantly reduce the glucose area. Drying conditions and cooking times could be varied within broad limits without affecting the rate of starch digestion in vitro of cooked spaghetti. In sterilized spaghetti the content of resistant starch was higher than that found in cooked 'al dente' spaghetti (2.2-3.4 vs 0.5 mg/100 mg total starch). In conclusion, sterilization influences the nutritional properties of starch in pasta by substantially increasing the glucose and insulin responses and by formation of resistant starch. The effect of oatbran environment is restricted mainly to a slight decrease in the insulin response.

Adult↗
PubMed1992

[Experiences in dealing with tubal sterilization].

The political changes in the GDR and the unity of Germany give the women the possibility of deciding for tubal sterilization as a method of contraception that was restrictively used in the GDR. This investigation analysis the psychosocial and medical factors influencing the women in their decision for sterilization. 103 women were interviewed with a questionnaire before they underwent tubal sterilization in a great medical center in Sachsen-Anhalt. The findings known in the literature regarding the satisfied after sterilization were discussed. However the sterilization is an intervention that should be thought over carefully.

Abortion, Induced↗
PubMedDate not supplied

Effectiveness of microwave sterilization on three hard chairside reline resins.

PURPOSE: The aim of this study was to evaluate the effectiveness of microwave irradiation sterilization on hard chairside reline resins. MATERIALS AND METHODS: Specimens of three reline resins (Kooliner, Tokuso Rebase, and Ufi Gel Hard) were fabricated and subjected to ethylene oxide sterilization. The specimens were then individually inoculated (10(7) cfu/mL) with Tryptic Soy Broth media containing one of the tested microorganisms (C albicans, S aureus, B subtilis, and P aeruginosa). After 48 hours at 37 degrees C, the samples were vortexed for 1 minute and allowed to stand for 9 minutes, followed by a short vortex to resuspend any organisms present. After inoculation, 40 specimens of each material were immersed in 200 mL of water and subjected to microwave irradiation at 650 W for 6 minutes. Forty non-irradiated specimens were used as positive controls. Replicate specimens (25 microL) of suspension were plated at dilutions of 10(-3) to 10(-6) on plates of selective media appropriate for each organism. All plates were incubated at 37 degrees C for 48 hours. After incubation, colonies were counted, and the data were statistically analyzed by the Kruskal-Wallis test. Twelve specimens of each material were prepared for SEM. RESULTS: All immersed specimens showed consistent sterilization of all the individual organisms after microwave irradiation. SEM examination indicated an alteration in cell morphology after microwave irradiation. CONCLUSION: Microwave sterilization for 6 minutes at 650 W proved to be effective for the sterilization of hard chairside reline resins.

Acrylic Resins↗
PubMedDate not supplied

Vaporized hydrogen peroxide sterilization of freeze dryers.

The feasibility of using vapor hydrogen peroxide (VHP) as an alternative to steam sterilization has been examined using a pilot plant freeze dryer equipped with a prototype vapor generator. Specific objectives of the study discussed in this presentation were to: 1. Identify critical process variables affecting the lethality of VHP to Bacillus stearothermophilus spores, particularly within dead legs in the system. 2. Measure the efficacy of system degassing after sterilization. 3. Determine the effect of repeated sterilization cycles on the integrity of elastomeric components of the freeze dryer. Penetration of adequate concentrations of hydrogen peroxide vapor into small diameter piping, such as tubing connected to pressure gauges, is the most challenging aspect of VHP sterilization of freeze dryers. Prior to equipment modifications, spore strips placed within such dead legs remained positive irrespective of the number of gas/degas pulses and system pressure. Equipment modifications necessary to effect complete kill of biological indicators placed in system dead legs is discussed. Results of this study support the conclusion that vaporized hydrogen peroxide shows promise as an alternative sterilization method for freeze dryers.

Equipment Design↗
PubMedDate not supplied

Comparison of different rubber stoppers; the effect of sterilization on the number of particles released.

The effect of sterilization on the number of particles released from five different types of rubber stoppers, as well as on their surface roughness and elemental composition before and after sterilization is described. The stoppers were immersed in 200 ml of 0.9% sodium chloride solution in conical flasks. The number of particles released into the sodium chloride solution was measured by Coulter Counter. The surface roughness and the elemental composition of the stoppers were determined by SEM/EDX. All measurements were made both before and after sterilization at 121 degrees C to F0 15 mins. The number of particles released from a stopper during sterilization varies considerably between different stoppers and even between different batches of the same stopper. The only non-siliconized stopper in this study performed well. The absence of surface siliconization may have contributed to this performance. The scanning electron micrographs revealed well the differences in the surface roughness of the stoppers. The sterilization generally increases the surface roughness of the samples. The x-ray microanalysis revealed that the elemental composition of the stoppers may vary not only between different types of stoppers but also between different batches of the same stopper.

Drug Packaging↗
PubMedDate not supplied

PD fluids contain high concentrations of cytotoxic GDPs directly after sterilization.

OBJECTIVE: Glucose degradation products (GDPs) in peritoneal dialysis (PD) fluids are cytotoxic and affect the survival of the peritoneal membrane. One of the most reactive GDPs in PD fluids is 3,4-dideoxyglucosone-3-ene (3,4-DGE). 3,4-DGE has been reported as an intermediate between 3-deoxyglucosone (3-DG) and 5-hydroxymethyl furaldehyde (5-HMF) during degradation of glucose. In PD fluids, 3,4-DGE exists in a temperature-dependent equilibrium with a pool of unidentified substances. The aim of this study was to explore this equilibrium and its temperature dependence during the first months of storage after the sterilization procedure. METHODS: GDPs and inhibition of cell growth (ICG) were measured directly after sterilization of the PD fluid and during storage at different temperatures for 60 days. The following GDPs were analyzed: 3-DG, 3,4-DGE, 5-HMF, formaldehyde, acetaldehyde, glyoxal, and methylglyoxal. RESULTS: Immediately after sterilization, the concentration of 3,4-DGE was 125 micromol/L. During the first weeks of storage, it decreased by about 80%. At the same time, the 3-DG concentration increased. None of the other GDPs were significantly affected. Cytotoxicity correlated well with the concentration of 3,4-DGE. When pure 3,4-DGE was substituted for the lost amount of 3,4-DGE after 30 days of storage, the initial ICG was almost completely regained. CONCLUSIONS: Heat sterilization of PD fluids promotes the formation of large quantities of 3,4-DGE, rendering the fluid highly cytotoxic. During storage, the main part of 3,4-DGE is reversibly converted in a temperature-dependent manner to a less cytotoxic pool, consisting mainly of 3-DG. Cytotoxicity seems to be dependent exclusively on 3,4-DGE. In order to avoid higher levels of 3,4-DGE concentrations, PD fluids should not be used too soon after sterilization and should not be stored at temperatures above room temperature.

Aldehydes↗