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The use of spore strips for monitoring the sterilization of bottled fluids.

A bacterial spore test has been developed which enables the efficacy of the sterilizing cycle recommended by the British Pharmaceutical Codex (1973) for bottled fluids to be accurately monitored. During a 14-month period this test detected faults in 3.3% of the sterilizing cycles, representing five distinct episodes of sterilization failure that passed unnoticed by the conventional controls of physical measurements and sterility testing. There were no failures of sterilization as detected by conventional techniques which were not indicated by the spore test.

Geobacillus stearothermophilus↗

Psychological sequelae of female sterilization: short-term outcome in a prospective controlled study. A report from the UK Field Research Centre of a WHO collaborative project.

Healthy multiparous women having elective interval (N = 69) or postpartum (N = 69) sterilization were interviewed pre-operatively and 6 weeks and 6 months post-operatively, using standardized instruments. They did not differ significantly from control samples of comparable non-sterilized women with respect to mental state (Present State Examination) or subjectively-assessed mental or physical health or abdominal pain. More sterilization subjects than control subjects reported subjectively experienced improvement in sexual satisfaction at the later follow-up. Reports of poor physical health and abdominal pain increased over time within both the sterilization and the control groups. Reports of adverse effects at follow-up were often associated with higher PSE scores initially. Regrets and wish for reversal were rare and were also associated with higher initial PSE scores. Since the adverse effects were more common among postpartum subjects, it is suggested that subjectively experienced sequelae of sterilization may sometimes be attributable to 'normal' postnatal events.

Abdomen↗

On-line sterilization of cheese whey using ultraviolet radiation.

The effectiveness of ultraviolet radiation for on-line sterilization of cheese whey was investigated. The effects of flow rate and residence time on the performance of three UV reactors having different gap sizes (18, 13, and 6 mm) were studied. Six flow rates and six residence times were tested with the three UV reactors. The cheese whey used in this study had a very high turbidity (4317 NTU), very poor transmittance in the UV radiation germicidal range ( approximately 0%), and high percentage of large solid particles ( approximately 20% > 100 microm). Although the cheese whey physical characteristics showed low probability of sterilization using UV radiation, the study showed that UV radiation can be used on-line to sterilize cheese whey if the proper reactor gap size and the appropriate residence time are used. There were combined effects of the flow rate and gap size. The cell removal efficiency increased with increases in residence time and decreases in the UV reactor gap size. Removal efficiency of 100% was not achieved in this study with the first UV reactor (18-mm gap size), whereas 100% removal efficiency was achieved with the second (13-mm gap size) and third (6-mm gap size) UV reactors at residence times of 2.0 and 0.5 h, respectively. The microbial decay rates achieved in this study were 4.94, 7.62, and 20.9 h(-)(1) using the first, second, and third UV reactor, respectively. Residence times of 3.3, 2.1, and 0.8 h would be required to completely destruct a microbial population of 5.95 x 10(6) cells/mL using the first, second, and third UV reactors, respectively. Although cheese whey sterilization using UV radiation seems to be a good alternative to pasteurization, increases in cheese whey temperature resulted in lamp fouling. If online sterilization is to be used, the fouling problem should be investigated and a maintenance scheme for the UV reactor should be developed.

Animals↗

A discrete-time multilevel mixture model for event history data with long-term survivors, with an application to an analysis of contraceptive sterilization in Bangladesh.

Event history models typically assume that the entire population is at risk of experiencing the event of interest throughout the observation period. However, there will often be individuals, referred to as long-term survivors, who may be considered a priori to have a zero hazard throughout the study period. In this paper, a discrete-time mixture model is proposed in which the probability of long-term survivorship and the timing of event occurrence are modelled jointly. Another feature of event history data that often needs to be considered is that they may come from a population with a hierarchical structure. For example, individuals may be nested within geographical regions and individuals in the same region may have similar risks of experiencing the event of interest due to unobserved regional characteristics. Thus, the discrete-time mixture model is extended to allow for clustering in the likelihood and timing of an event within regions. The model is further extended to allow for unobserved individual heterogeneity in the hazard of event occurrence. The proposed model is applied in an analysis of contraceptive sterilization in Bangladesh. The results show that a woman's religion and education level affect her probability of choosing sterilization, but not when she gets sterilized. There is also evidence of community-level variation in sterilization timing, but not in the probability of sterilization.

Adolescent↗

Development of autologous human dermal-epidermal composites based on sterilized human allodermis for clinical use.

The aim of this study was to identify a sterilization technique for the preparation of human allodermis which could be used as a dermal component in wound healing and as the dermal base for production of dermal-epidermal composites for one-stage grafting in patients. We report that it is possible to produce dermal-epidermal composites which perform well in vitro and in vivo using a standard ethylene oxide sterilization methodology. Prevention of ethylene oxide-induced damage to the dermis was achieved using gentle dehydration of the skin prior to ethylene oxide sterilization. The issue of whether viable fibroblasts are required for composite production was examined in comparative studies using glycerol vs. ethylene oxide sterilized dermis. Where good collagen IV retention was achieved following preparation of acellular de-epidermized dermis there was no advantage to having fibroblasts present in vitro or in vivo; however, where collagen IV retention was poor or where keratinocytes were initially expanded in culture then there was a significant advantage to introducing fibroblasts to the composites during their preparative 10-day period in vitro. The requirement for fibroblasts became less evident when composites were grafted on to nude mice. In conclusion, we report a protocol for the successful sterilization of human allodermis to achieve an acellular dermis with good retention of collagen IV. This acellular dermis would be appropriate for clinical use as a dermal replacement material. It can also be used for the production of dermal-epidermal composites using autologous keratinocytes (with or without fibroblasts).

Adult↗

Sterilization of instruments in solar ovens.

AIMS: The sterilization of instruments in rural health clinics in less developed countries is an increasing problem as chemical methods can no longer be recommended and fuel wood is becoming increasingly scarce. It seems obvious, therefore, to utilize solar energy for sterilization purposes. METHODS AND RESULTS: A solar oven was designed and manufactured using local materials and simple tools. It was tested by physical, chemical and microbiological methods and, after successful testing, installed in a rural clinic. The oven was able to generate temperatures above 180 degrees C. On days with direct sunlight the oven fulfilled the international recommendations for hot air sterilization. The chemical indicators, Browne's tubes type 3 and 5, also changed colour. It was difficult to reach the right value for the sterilization effect during months with a low sun position. A moveable oven, or two ovens, must be installed to solve this problem. CONCLUSIONS: The solar oven has proven to be a realistic method for the sterilization of instruments. SIGNIFICANCE AND IMPACT OF THE STUDY: The solar oven is easy to make and use. It saves fuel and can be used in most tropical areas.

Developing Countries↗

The use of gamma irradiation for the sterilization of enamel for intra-oral cariogenicity tests.

The dose of gamma irradiation sufficient to sterilize enamel samples to be used for intra-oral cariogenicity tests (ICT) without alteration to the structure or solubility of the enamel was determined. Each bovine incisor used was cut vertically into eight portions and each portion assigned to one of eight groups. Group 1 was used as control while other groups were subjected to respective doses of gamma irradiation from a cobalt-60 source. Following sterilization, both control and experimental groups were incubated in nutrient broth for 7 days at 37 degrees C under aerobic and anaerobic conditions. Caries-like lesions were subsequently produced in each specimen using acidic buffer solution, and mineral loss quantified using transverse microradiography. Data were analysed statistically. There was no significant difference in mineral loss between the control and experimental groups, but the numerical value of mineral loss was lower in groups irradiated with> 4080 Gy, in addition to full sterilization and enamel discoloration to cream colour observed in these groups. Microbial growth was observed in the control group and in groups irradiated with <4080 Gy but no discoloration. With 4080 Gy full sterilization without discoloration was observed. It was concluded that 4080 Gy of gamma irradiation is optimal for sterilization of enamel samples for use in ICT.

Analysis of Variance↗

Outbreak of sterile peritonitis among continuous cycling peritoneal dialysis patients.

BACKGROUND: Approximately 30,000 patients receive peritoneal dialysis in the United States. In August 1996, several dialysis centers from different states reported sterile peritonitis among CCPD patients using sterile peritoneal dialysis solution (PDS) from a single manufacturer. The manufacturer recalled 53 lots of PDS that had passed established industry guidelines and Food and Drug Administration (FDA) approved quality control tests [including endotoxin levels <0.5 endotoxin units (EU)/ml], but had pre-sterilization bacterial colony counts >1 cfu/ml. METHODS: At one outpatient dialysis center, Hospital of the University of Pennsylvania (HUP), we conducted a retrospective cohort study of all CCPD patients treated during July 15 to August 30, 1996. A case-patient was defined as any HUP patient with culture-negative peritoneal fluid with a white blood cell count >100/mm3, cloudy peritoneal fluid, and/or abdominal pain. PDS and tubing were cultured for bacteria and assayed for endotoxin. RESULTS: Overall, 14 of 28 patients had sterile peritonitis. The only risk factor identified was exposure to > or =1 lot of recalled PDS (14 of 22 vs. 0/6, P = 0.02); the more recalled lots received, the higher the attack rate (P = 0.0001). Five of 47 PDS bags had detectable endotoxin; recalled lots were more likely to have measurable endotoxin than nonrecalled lots (5/19 vs. 0/17, P = 0.05). When case-patients resumed CCPD using PDS from non-recalled lots, no further cases were reported. CONCLUSIONS: Our results suggest that this outbreak was caused by intrinsic PDS contamination with endotoxin. Pre-sterilization colony counts may be an important quality control indicator for CCPD fluids in conjunction with endotoxin levels.

Adult↗

The effect of sterilization on transforming growth factor beta isolated from demineralized human bone.

Growth factors have been identified as the primary cause of osteoinduction in bone healing. Transforming growth factor beta (TGF-beta) has been shown to promote bone formation and is present in bone in high quantities. The aims of the present study were to isolate TGF-beta from human bone, demonstrate its biologic activity, and analyze the effects of conventional sterilization techniques on activity. Bone, obtained from femoral heads of five patients (mean age, 70 years) was ground, demineralized, and freeze-dried, and samples from each patient were divided into three groups: no treatment, sterilization with 1.60 to 1.94 Mrad of 60Co irradiation, and sterilization with ethylene oxide (ETO). Carrier-free recombinant TGF-beta control was also treated and was totally inactivated by ETO but not by irradiation (p < 0.01). TGF-beta activity in demineralized bone was not significantly diminished (p > 0.1) by either sterilization procedure, and substantial amounts of active TGF-beta were recovered in all bone samples: 1.04 +/- 0.77 ng per mg of protein in irradiated samples, 0.67 +/- 0.26 ng per mg in ETO-treated samples, and 1.04 +/- 0.33 in untreated samples, respectively (mean +/- SD). Although a recent report demonstrated that the osteoinductive activity of bone morphogenetic protein in bone powder is diminished considerably by ETO and by 2.5 Mrad of irradiation sterilization of bone powder, these data demonstrate that TGF-beta activity, with its osteoinductive properties, was not destroyed in more coarsely ground, demineralized bone by ETO or by lower doses of irradiation. These findings support the use of human bone allografts in clinical instances involving impaired bone formation.

Aged↗

Gas sterilization of fiber endoscopes.

Excitants of disease can be transmitted by endoscopes from one patient to another. Owing to their complicated construction and the heat-sensitive material fiber glass endoscopes are difficult to disinfect or sterilize. Of the known procedures of sterilization only gas sterilization with ethylene oxide can be used. Clinical examinations and laboratory experiments demonstrate the reliable efficacy of this procedure of sterilization of fiber glass endoscopes. On account of known risks the indications for gas sterilization are compiled.

Bacteria↗

[Tubal pregnancy following tubal sterilization].

The present paper reports on 21 tubal pregnancies which have occurred after tubal sterilization in Tübingen or elsewhere since 1975. The proportion of tubal pregnancies amongst sterilization failures was 75%. The interval between sterilization and the occurrence of the tubal pregnancy ranged between 5 months and 7-3/4 years. The most frequent symptoms of the tubal pregnancies were pain (15/21), amenorrhea (11/21) and vaginal bleeding (5/21). Only 11 of the 21 patients were admitted to the clinic with the (suspected) diagnosis of an extra-uterine pregnancy. In 20 of the 21 patients the pregnancy was located in the distal (ampullar) segment of the tube; in 8 cases the tube was ruptured. Thirteen patients were treated by bilateral and 5 by unilateral salpingectomy, and a further 3 by unilateral adnexectomy. Summarizing, a considerable number of pregnancies occurring after unsuccessful tubal sterilization are extra-uterine. They are often not recognized, or only at a late stage. In the authors' view the patient should be informed of the possibility of a tubal pregnancy prior to sterilization.

Adult↗

Sterilizing effects of trimethylphosphate in Drosophila melanogaster.

Trimethylphosphate (TMP) causes aspermia in D. melanogaster males. If larvae are allowed to develop on standard maize-meal medium containing 0.002 M TMP or greater, the enclosing adult males, when placed on uncontaminated medium, exhibit a period of temporary sterility. Between test groups the period of sterility is most variable at the doses of 0.002-0.004 M, but at 0.005 M or greater is approximately 11-12 days. Near-lethal doses of about 20 g/kg by abdominal injection produces a temporary sterility in adults, whereas oral doses up to 0.02 M are ineffective. Oogenesis in females is not affected by doses which cause temporary sterility in males. In adult male D. melanogaster, which were treated as larvae with 0.01 M TMP in the food medium, the basal region of testes and seminal vesicles do not contain spermatozoa. Cytological examinations of the spermatids reveal ultrastructural changes which are characteristic of those seen in X/O and sterile-mutant males; they contain incomplete axial fibre complexes, abnormal development of the mitochondrial derivatives, and nuclei which fail to elongate and condense. Evidence from cytological studies of larval testes suggests that the chemosterilizing effect of TMP is upon early primary spermatocytes. This is also supported by mating data.

Animals↗

Sterilized ibuprofen-loaded poly(D,L-lactide-co-glycolide) microspheres for intra-articular administration: effect of gamma-irradiation and storage.

The aim of this study was to prepare and characterize a controlled-release system (microspheres) loaded with ibuprofen, for intra-articular administration, to extend its anti-inflammatory effect in the knee joint cavity. Among the bioresorbable polymers employed, poly(D,L-lactic-co-glycolic) acid (PLGA) (13137 Da) was chosen because of its high biocompatiblity. Microspheres were produced by the solvent evaporation process from an O/W emulsion. Labrafil M 1944 CS was included in the formulation as an additive in order to modulate the release rate of the non-steroidal anti-inflammatory drug (NSAID). Once prepared, the microspheres were sobre-sterilized by gamma-irradiation. The effect of the irradiation dose (25 kGy) exposure, at low temperature, on the formulation was evaluated. The sterilization procedure employed did not alter the physicochemical characteristics of the formulation. Dissolution profiles of formulations behaved similarly and overlapped (f2=87.23, f1=4.2) before and after sterilization. Size Exclusion Chromatography (SEC) revealed no significant changes in the polymer molecular weight. Additionally, a stability study of the sterilized formulation was carried out using microsphere storage conditions of 4 degrees C in a vacuum desiccator for 1 year. The results obtained after storing the sterilized microspheres show no significant alterations in the ibuprofen release rate (f2 = 85.06, f1 = 4.32) or in the molecular weight of the PLGA (12957 Da). The employment of low molecular weight PLGA polymers resulted as advantageous, due to the practical absence of degradation after gamma irradiation (25 kGy) exposure at low temperature.

Anti-Inflammatory Agents, Non-Steroidal↗

Personal exposure level and environmental ethylene oxide gas concentration in sterilization facilities of hospitals in Japan.

Personal and environmental (stationary) ethylene oxide (EO) gas concentrations in gas sterilization facilities were measured at six workplaces in five hospitals. An ethylene oxide gas monitor (3M #3551) was used for both personal and stationary samplings. A gas detector tube was also used for instantaneous sampling. In most workplaces, the personal exposure levels of EO were below the detection limit of the gas monitor. Most of the time-weighted average (TWA) concentrations by the stationary sampling were below the threshold limit value of EO (TLV-TWA = 1 ppm), but in one workplace, more than 4 ppm of EO were detected in front of the sterilizer in a clean room during a 24-hour measurement, although all the personal exposure levels were below the detection limit. Method of aeration after the sterilization was very important for reducing the EO exposure. The EO gas concentrations in two workplaces where sufficient aeration was carried out were below the detection limit in all the stationary samples. In one workplace where insufficient aeration was performed, EO was detected from 16 of 17 stationary samples, and more than 90-200 ppm of EO was determined by the gas detector tube near the worker's face at the moment when the door of the sterilizer was opened and the sterilized materials were removed.

Air Pollutants, Occupational↗

Evaluation of a rapid readout biological indicator for 121 degrees C gravity and 132 degrees C vacuum-assisted steam sterilization cycles.

OBJECTIVE: A biological indicator (BI), based on fluorescent detection of a spore-associated enzyme, has been developed. We evaluated the new BI against five conventional self-contained BIs in a 121 degrees C gravity-displacement sterilizer and, packaged in towel packs and disposable steam test packs, in a 132 degrees C vacuum-assisted sterilizer. DESIGN: In the 121 degrees C gravity-displacement sterilizer, rapid readout BIs and conventional BIs were tested together in an otherwise empty chamber. Exposure times were 5, 10, and 15 minutes. In the 132 degrees C vacuum-assisted steam sterilizer, BIs were contained in towel packs or disposable steam test packs. Surgical packs were added to represent a full load. Exposure times were 0, 1, and 2 minutes. RESULTS: In gravity-displacement 5-minute cycles, the rapid readout BIs yielded 100% positive results within 30 minutes. The conventional BIs ranged from 72% to 100% positive in 48 hours. At 10 minutes, the rapid readout BIs were 83% positive after 3 hours, whereas the conventional BIs ranged from 0% to 37% positive after 48 hours. All indicators were negative after 15-minute exposures. In vacuum-assisted cycles, all indicators were negative after 3 minutes. After 1-minute exposures, the rapid readout BIs were 40% to 60% positive, whereas the conventional BIs were 15% to 20% positive. CONCLUSION: The rapid readout BIs are a more sensitive indicator of marginal steam sterilization cycles than conventional self-contained BIs. They yield results within 3 hours, as compared to 24 to 48 hours for the conventional BIs.

Evaluation Studies as Topic↗

The benefits of using the loop ligature (Endoloop) laparoscopic sterilization procedure in a residency program.

This study was conducted to determine the impact of the addition of the loop ligation (Endoloop) technique on choice of sterilization surgery in our residency teaching program and to investigate significant differences between this technique and other methods performed at our hospital. A retrospective study of all patients undergoing interval tubal sterilization at Tampa General Hospital in 1989 and 1991 was undertaken. Data were analyzed to determine the frequency of sterilization methods and differences between the loop ligation method and the other procedures performed; p values of less than 0.05 were considered significant. Sixty-one patients in 1989 and 75 in 1991 qualified for the study. Five methods of interval sterilization were performed: loop ligation, minilaparotomy, colpotomy, laparoscopic bipolar fulguration, and Silastic ring application. The frequency of the loop ligature technique increased from 0% in 1989 to 40% in 1991. There were no significant differences in operative time and complication rate among the loop method and other procedures. The loop ligature (Endoloop) method of laparoscopic sterilization does not significantly change the length of surgery, blood loss, or complication rate compared to the other laparoscopic techniques used in our residency program. This method provides a definitive tissue diagnosis, eliminates the risk of thermal injury, theoretically provides an opportunity of later tubal reanastomosis, and subjectively helps develop laparoscopic skills.

Female↗

Hysteroscopic permanent tubal sterilization using a nitinol-dacron intratubal device without anaesthesia in the outpatient setting: procedure feasibility and effectiveness.

BACKGROUND: Hysteroscopic permanent tubal sterilization has recently been introduced, resulting in a non-invasive, safe and effective technique. The aim of this study was to assess the feasibility of outpatient hysteroscopic tubal sterilization using a nitinol-dacron intratubal device without anaesthesia and to assess patient procedure compliance. MATERIALS AND METHODS: We untertook a prospective study of 36 consecutive cases of outpatient hysteroscopic tubal sterilization using a nitinol-dacron intratubal device without anaesthesia. Tubal sterilization was performed by placing the device with the aid of a 5.2-mm continuous-flow operative hysteroscope. At the end of the procedure women were asked to rate the pain experienced on a visual analogue scale (VAS) (0, no discomfort to 100, severe discomfort). Successful device placement was assessed after 3 months by hysterosalpingography and diagnostic hysteroscopy. RESULTS: Successful bilateral placement was obtained in 32 patients (88.9%); in one (2.8%) the placement was monolateral; and in three (8.3%) the procedure failed. Mean operating time was 8.6 +/- 5.3 min. A mean VAS of 36.1 +/- 23.9 was recorded. CONCLUSIONS: The nitinol-dacron intratubal device is safe, appears to be effective long-term, is non-invasive and can be used in the outpatient setting without anaesthesia. Low-level discomfort was experienced by the patients. Limitations of its use include that it is not effective immediately, it is irreversible, it requires special equipment and training, and it is difficult to use in cases of uterine anomalies. We conclude that this method may be offered to all woman asking for permanent tubal sterilization, particularly those who refuse or have contraindications for anaesthesia.

Adult↗

Sterility of anesthetic and resuscitative drug syringes used in the obstetric operating room.

UNLABELLED: Because of the constant threat of emergent cesarean delivery, anesthetic induction and resuscitation drugs are often drawn into syringes and stored in the obstetric operating room (OR). This study investigated the potential for bacterial and fungal contamination of six drugs (thiopental, succinylcholine, ephedrine, atropine, lidocaine, and oxytocin) often prepared in the obstetric OR. A total of 756 drug syringes were prepared and stored in the obstetric OR for 8 days using normal clinical practices. Starting on Day 0, and subsequently on Days 4 and 8 of the experiment, 42 syringes of each drug were randomly selected from the pool, filtered through a 0.45-microm porosity sterile cellulose filter, and cultured on 5% sheep blood agar. Of the 756 syringes tested, none grew organisms of any type, which indicates a probability of drug sterility of > or = 0.9961 (95% confidence interval [CI]). The data from the cultures performed on syringes on Day 0 indicate a probability of initial contamination of < or = 0.018 (95% CI). This study demonstrates a high probability of sterility in drugs drawn into sterile syringes and stored at room temperature in an OR environment for up to 8 days. IMPLICATIONS: Drug syringes stored in emergency operating rooms are discarded after 24 h because of possible contamination. We searched for microorganisms in drug syringes stored in the operating room for up to 8 days. No microbes were detected using standard sterility testing techniques. Adopting longer storage periods could result in significant cost savings.

Anesthesia, Obstetrical↗