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PubMed1997

Effectiveness of salt versus glass bead sterilizers.

Microorganisms can be removed from dental instruments by various methods, including treatment in salt and glass bead sterilizers. However, no rigorous, controlled, in vivo or in vitro studies have been performed to verify the respective efficiencies of these methods. The goals of this study were to determine if the positioning of instruments at the centre or edge of a salt sterilizer results in differential sterilization effectiveness, and to compare the effectiveness of salt sterilizers relative to glass bead sterilizers. Autoclaved number 60 reamers were contaminated by plunging them to the handle in a commercial Bacillus stearothermophilus spore suspension. They were then sterilized for different periods of time and at different positions in the sterilizers. Each experiment included positive and negative controls. The results showed that better sterilization is achieved at the edge of the chamber than at the centre, and that salt sterilizers are more effective than glass bead sterilizers for a given period of time (15 seconds) in the sterilizer.

Culture Media↗
PubMed2006

[Male and female sterilization techniques: Summary of ANAES assessments (May 2005)].

OBJECTIVE: To summarize assessments carried out by ANAES on male and female sterilization techniques. The summary was requested by the French Health Directorate after the law authorizing sterilization as a means of contraception was passed. RESULTS (FEMALE STERILIZATION): (i) EFFICACY of tubal ligation, electrocoagulation, clips or rings: the annual pregnancy rate is 0-2% depending on the study, with no significant difference between techniques. No data were found on fimbriectomy. (ii) EFFICACY of a hysteroscopically placed micro-insert device: no pregnancies were observed in patients with bilateral tube obstruction diagnosed by hysterosalpingography at 3 or at 6 months after placement (placement rate: 87-89%). (iii) SAFETY of tubal ligation, electrocoagulation, clips or rings: (a) By approach: There was no difference in the incidence of major complications between laparoscopy and minilaparotomy but there were significantly fewer minor complications with laparoscopy than with minilaparotomy. There were significantly more major complications with culdoscopy than with minilaparotomy and significantly more minor complications than with laparoscopy. (b) By operative technique: major and minor complications were significantly more common with the Pomeroy technique than with electrocoagulation; the difference could be due to the approach used. No data were available on fimbriectomy. (iv) SAFETY of a hysteroscopically placed micro-insert device: there were 11 cases of myometrial or tubal perforation among 734 patients (with device displacement into the peritoneal cavity in 3 cases). RESULTS (MALE STERILIZATION): (i) EFFICACY: efficacy varied from 84% to 100% depending on the approach and the mode of vas deferens obstruction. There was no significant difference in efficacy according to approach (transcutaneous or scrotal). However, no conclusion could be drawn on the comparative efficacy of the occlusion techniques used from published data. (ii) SAFETY: the rate of postoperative complications was low, below 10% in most series. Complications were benign and only rarely necessitated surgical revision. CONCLUSION: The advantage of sterilization methods is that they lack any permanent contraindication. They should be presented as being generally irreversible. Fimbriectomy is not recommended for female sterilization. Laparoscopy is the preferred approach. Sterilization by hysteroscopic placement of a micro-insert device should be restricted to cases presenting a risk on laparoscopy; the technique should be re-assessed in 2006. The two approaches used for male sterilization are technically similar and do not seem to differ in efficacy. The Public Health Code states that "Fallopian tube or deferens duct ligation for contraceptive purposes is not allowed in minors" and that ligation "cannot be performed unless the adult involved has given his/her informed and motivated consent, expressed after taking into consideration clear, complete information on the consequences of the procedure". A waiting period of four months must follow the moment the decision to sterilize is taken and consent is given. An informed consent form must be signed. Sterilization in young or nulliparous women should be proposed with the greatest prudence and with many reservations.

Adolescent↗
PubMedDate not supplied

Beliefs about contraceptive sterilization among low-income urban women.

Among a group of low-income clinic patients planning to be sterilized, the vast majority--95 percent--reported believing that sterilization is the surest way to avoid getting pregnant and that it is safer than other contraceptive methods. Among a comparison group who also wanted no more children but did not plan to be sterilized, the majority also held these beliefs, but the proportion was lower (76-80 percent). In both groups, however, only between 64 and 70 percent knew that sterilization makes it impossible to have children in the future. Between 63 and 68 percent of the women in the sterilization group believed that having the operation would improve their family relationships, emotional state and other aspects of their lives, but only 35-58 percent of the comparison group held these beliefs. On the other hand, women in the comparison group were more likely than those in the sterilization group to believe that sterilization has negative health and psychological effects--for example, changes in menses (more bleeding or cramping) or defeminization. The beliefs held by both groups suggest that it is a conviction regarding the advantages of sterilization, rather than a relative unawareness of the disadvantages, that distinguishes women who plan to be sterilized from those who, although they want no more children, do not have similar plans. The study results have implications for family planning professionals: Counselors need to be aware that some women seeking sterilization may not understand its permanency or may have an unrealistic appraisal of its potential effect on their lives.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2003

Assessing hybrid sterility in Oryza glaberrima x O. sativa hybrid progenies by PCR marker analysis and crossing with wide compatibility varieties.

Interspecific crossing of the African indigenous rice Oryza glaberrima with Oryza sativa cultivars is hindered by crossing barriers causing 100% spikelet sterility in F(1) hybrids. Since hybrids are partially female fertile, fertility can be restored by back crossing (BC) to a recurrent male parent. Distinct genetic models on spikelet sterility have been developed predicting, e.g., the existence of a gamete eliminator and/or a pollen killer. Linkage of sterility to the waxy starch synthase gene and the chromogen gene C, both located on chromosome 6, have been demonstrated. We selected a segregating BC(2)F(3) population of semi-sterile O. glaberrima x O. sativa indica hybrid progenies for analyses with PCR markers located at the respective chromosome-6 region. These analyses revealed that semi-sterile plants were heterozygous for a marker (OSR25) located in the waxy promoter, whereas fertile progenies were homozygous for the O. glaberrima allele. Adjacent markers showed no linkage to spikelet sterility. Semi-sterility of hybrid progenies was maintained at least until the F(4) progeny generation, suggesting the existence of a pollen killer in this plant material. Monitoring of reproductive plant development showed that spikelet sterility was at least partially due to an arrest of pollen development at the microspore stage. In order to address the question whether genes responsible for F(1) sterility in intraspecific hybrids ( O. sativa indica x japonica) also cause spikelet sterility in interspecific hybrids, crossings with wide compatibility varieties (WCV) were performed. WCV accessions possess "neutral" S-loci ( S(n)) improving fertility in intraspecific hybrids. This experiment showed that the tested S(n)-loci had no fertility restoring effect in F(1) interspecific hybrids. Pollen development was completely arrested at the microspore stage and grains were never obtained after selfing. This suggests that distinct or additional S-loci are responsible for sterility of O. glaberrima x O. sativa hybrids.

Chimera↗
PubMed1991

The evolutionary history of D. buzzatii. XXII. Chromosomal and genic sterility in male hybrids of Drosophila buzzatii and Drosophila koepferae.

The genetic basis of sterility in F1 male hybrids of Drosophila buzzatii and D. koepferae has been investigated in two steps. (1) By successive backcrossing of hybrid females to either parental species. (2) By assessment of the effects on male fertility of selected segments of polytene chromosomes from the donor species on a background entirely derived from the recipient species. The length of introgressed segments producing sterility was progressively reduced through repeated backcrosses. This procedure sometimes led to an approximate mapping of major genes of hybrid sterility (genic sterility) on the polytene chromosome map. At other times it was found that sterility was produced only when the introgressed segment exceeded a certain threshold size (chromosomal sterility). The contribution of the autosomes to hybrid sterility seems to be mainly of the chromosomal type. The evidence concerning the X chromosome is equivocal. No fertile males were found following introgression with any of the investigated segments of this chromosome. These results are compatible both with the presence of at least six major genes of hybrid sterility (genic sterility) and with the existence of a rather small threshold size for the chromosome segments producing sterility (chromosomal sterility). The role of the Y chromosome was not investigated in this study.

Animals↗
PubMed2004

Nuclear-cytoplasmic male-sterility in diploid dandelions.

Male-sterility was found in diploid dandelions from two widely separated populations from France, and its inheritance was analysed by crossing a diploid male-sterile dandelion to diploid sexuals and triploid apomicts. Nuclear genetic variation, found in full-sib families, segregated for male-fertility, partial male-sterility, and full male-sterility, and also segregated for small-sized versus normally sized pollen. The crossing results are best explained by a cytoplasmic male-sterility factor in combination with two dominant restorer genes. Involvement of the cytoplasmic male-sterility factor was further investigated by chloroplast haplotyping. Male-sterility was exclusively associated with a rare chloroplast haplotype (designated 16b). This haplotype was found in seven male-sterile plants and one (apparently restored) male-fertile individual but does not occur in 110 co-existing male-fertile plants and not in several hundreds of individuals previously haplotyped. Apomicts with cytoplasmic male sterility were generated in some test crosses. This raises the question as to whether the male sterility found in natural dandelion apomicts, is of cytoplasmic or of nuclear genetic nature. As many breeding systems in Taraxacum are involved in shaping population structure, it will be difficult to predict the evolutionary consequences of nuclear-cytoplasmic male-sterility for this species complex.

Cell Nucleus↗
PubMedDate not supplied

Sterility in zambia.

BACKGROUND: Several regions such as Zambia in sub-Saharan Africa experience very high levels of sterility. Current explanations for high levels of sterility in Zambia have focused on biological determinants and have paid little attention to the plausible effects of social determinants of sterility. AIM: This study has two objectives. The first objective is to examine the extent of sterility in Zambia during 1980 and 1990. The second objective is to assess the contribution of selected social determinants to the current levels of sterility in Zambia. SUBJECTS AND METHODS: Sterility among women in Zambia is calculated for two periods in 1980 and 1990 using census data. The study used parity progression ratios for the calculation of sterility rates. Selected social determinants of Zambian sterility were obtained from the Demographic Health Survey (ZDHS). Net effects of selected social determinants were examined using logistic regression. RESULTS: High sterility levels were found in a few Zambian Provinces. During 1980 and 1990, the rates for North Western, Eastern and Western provinces remained considerably higher than for other Zambian provinces. It was found that social level variables remained strong and significant even after controlling for the effects of incidence of biological factors such as sexually transmitted diseases (STDs). CONCLUSIONS: The findings of the study support the importance of developing social policies for eradicating sterility. The argument that sterility is biological and that it is not amenable to social interventions perhaps needs revision in the light of the findings of this study.

Adolescent↗
PubMed2004

Genetic complexity underlying hybrid male sterility in Drosophila.

Recent genetic analyses of closely related species of Drosophila have indicated that hybrid male sterility is the consequence of highly complex synergistic effects among multiple genes, both conspecific and heterospecific. On the contrary, much evidence suggests the presence of major genes causing hybrid female sterility and inviability in the less-related species, D. melanogaster and D. simulans. Does this contrast reflect the genetic distance between species? Or, generally, is the genetic basis of hybrid male sterility more complex than that of hybrid female sterility and inviability? To clarify this point, the D. simulans introgression of the cytological region 34D-36A to the D. melanogaster genome, which causes recessive male sterility, was dissected by recombination, deficiency, and complementation mapping. The 450-kb region between two genes, Suppressor of Hairless and snail, exhibited a strong effect on the sterility. Males are (semi-)sterile if this region of the introgression is made homozygous or hemizygous. But no genes in the region singly cause the sterility; this region has at least two genes, which in combination result in male sterility. Further, the males are less fertile when heterozygous with a larger introgression, which suggests that dominant modifiers enhance the effects of recessive genes of male sterility. Such an epistatic view, even in the less-related species, suggests that the genetic complexity is special to hybrid male sterility.

Alcohol Dehydrogenase↗
PubMed2005

[Establishment of Genic Male Sterile Lines of Brassica napus by Wide Cross and Their Cytology and Morphology.].

One and three male sterile plants were found in the progenies of the intergeneric hybrids by crossing Brassica napus and Brassica juncea to Orychophragmus violaceus, respectively. After interspecific cross and full-sib crosses, four genic male sterile lines were obtained. The results of cytological observations indicated that somatic chromosome number was 38 in all types of sterile lines, which were considered as the type of B. napus. Most of pollen mother cells (PMC) in all sterile plants were observed normally for chromosome behaviour. But abnormal phenomena of chromosome, which present for chromosome lagging and bridge, were still found at each stage of meiosis in these sterile lines. These lines belonged to complete sterile type. There were distinct differences between sterile plants and normal plants in the flower morphology. Bud death at different degrees was found on anthotaxies in sterile plants. Studies on the flower growth showed that the growths of the pistils in sterile plants were gradually accelerated along with pollen sterility. At the same time there were two slowly growth stages of the pistils growth in normal plants. The prospects of these sterile lines were discussed in this paper.

Brassica napus↗
PubMed1964

SURVEY ON PREVACUUM HIGH-PRESSURE STEAM STERILIZERS.

None of the 10 prevacuum high-pressure sterilizers of different makes tested was able to produce and maintain the conditions advocated by the Medical Research Council working party on high-pressure steam sterilizers (1959) or by Knox and Penikett (1958) with the result that steam did not penetrate adequately the single challenge load and it was not sterilized. The sterilization of ;group drums' of various sizes and contents was erratic and tended to give operators a false sense of security. An alarming number of minor engineering faults were present in seven out of 10 machines tested and they require very much more skilled maintenance than is being given at the moment. The possibility of centralizing sterilizers to central sterile supply departments and placing them under the care of a regional engineer cannot be too highly recommended. The presence of undetected ;leaks' and a failure to draw a prevacuum of 20 mm. even with a steam burst interferes with sterilization of a challenge load. A leak test should be performed twice daily and should not exceed more than 1 mm. in one minute at 20 mm. absolute. The centre of the load should be monitored by crossed tapes or Brownes tubes in each sterilizing cycle. Although the challenge load was sterilized when the chamber was filled to capacity, a more reliable cycle consisting of a double prevacuum of 20 mm. or more with intermediate steam burst to 10 lb. ensured the sterilizing of a single challenge load, which could be adequately controlled by the chamber drain temperature.

Engineering↗
PubMed1984

Complications of female sterilization: immediate and delayed.

Surgical sterilization in women has changed dramatically over the past 20 years. The development of laparoscopy and minilaparotomy have made the procedure readily available even in developing countries. In the United States, changing social values and changes in hospital regulations have done as much as technology to account for the tremendous increases in the number of women undergoing sterilization. Improved sterilization procedures have resulted in lower costs for sterilization and lowered morbidity and mortality rates. Hysterectomy for sterilization alone carries unacceptable morbidity and mortality rates. Originally, laparoscopic techniques utilized unipolar cautery. However, bowel burns, a rare but serious complication, were reported, and this led to newer techniques. These techniques, using bands, clips, and bipolar cautery, have gained increasing popularity and have eliminated many of the serious complications of female sterilization. Historically, there has been concern that tubal sterilization by any method produces, in significant numbers of patients, the subsequent gynecologic and psychologic problems called "post-tubal ligation syndrome." A review of earlier literature indicates that many of these studies have serious methodologic problems, including recall bias, inappropriate control groups, failure to elicit prior history of gynecologic or psychologic problems, and failure to account for the use of oral contraceptives or IUDs. More recent large prospective epidemiologic studies that have controlled for prior gynecologic problems and contraceptive usage have failed to show increased incidence of gynecologic sequelae in large numbers of women. However, there are some data to support the concept that in certain individuals, sterilization may result in disruption of ovarian blood or nerve supply, producing gynecologic sequelae. Additional data from these ongoing large-scale studies and others should help to elucidate this problem in the future. Pregnancy after sterilization (even excluding pregnancies present at the time of the procedure) is more common the first year after the procedure with the risk decreasing in subsequent years.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrocoagulation↗
PubMed1997

Female and male sterilization and refertilization in Sweden.

In Sweden, approximately 1,500 men and 7,000 women are sterilized yearly. The frequency varies considerably between regions. The reasons for these differences are not fully known. More women than men are sterilized in Sweden, but a higher proportion of sterilized men undergo refertilization. The object of the study was to analyze counselling routines prior to sterilization, presterilization waiting time, the number of refertilizations performed, the attitudes of the operating departments towards refertilization, and the possible relation between frequency of refertilization and incidence of sterilization. A questionnaire was mailed to all units performing refertilizations and/or sterilizations of mean and women in Sweden (n = 161). The response was 93%. Counselling routines and waiting times before sterilization varied, which influenced the operation's availability. The frequency of refertilizations varied considerably between counties from 0.5 to 5.4 per 100,000 inhabitants. There was no correlation between frequency of sterilizations and refertilizations. The rate of refertilization appears to be determined mostly by the local attitudes of the health authority. The Swedish sterilization law has had a heterogeneous impact in the country.

Adult↗
PubMed1991

The effects of different steam-sterilization programs on material properties of poly(L-lactide).

As-polymerized poly(L-lactide) test rods were sterilized by seven different specially designed computer-operated autoclaving programs. As a control, common hospital sterilization was performed. In all cases, the molecular weight decreased after sterilization. A short time high-temperature sterilization led to less molecular weight decrease than a low sterilization temperature cycle with a longer sterilization time. Regular hospital sterilization significantly reduced the elongation at break and also resulted in a decrease of 35% in tensile strength. The program causing minimal damage to the material properties was studied in detail. This program, with a sterilization period of 60 s and 129 degrees C, was effective for PLLA sterilization and also looks very promising for sterilization of other thermo- and moisture-labile polymers.

Humans↗
PubMed2001

Fat content and fatty acid composition of fresh, pasteurized, or sterilized human milk.

In hospitals, human milk is subjected to heat treatment to reduce risk of transmission of infectious agents such as human immunodeficiency virus (HIV), hepatitis B, cytomegalovirus, and bacterial contamination, especially during feeding of banked milk to preterm infants. Fat losses due to heat treatment have been extensively studied in cow milk but have received little attention in human milk. We studied the effect of human milk pasteurization and sterilization on total fat content available to the infant as well as on fatty acid composition. Milk samples from 12 mothers (days 5-35 of lactation) were divided into three equal parts: one remained fresh, one was pasteurized (62.5 degrees C for 30min), and one was sterilized (120 degrees C for 30min). Fat content was determined gravimetrically, and the contribution of 30 fatty acids was determined by gas chromatography. For investigation of loss of available fat in sterilized milk, milk was collected from two additional mothers and analyzed with a modified extraction method. Total fat content was the same in fresh, pasteurized, and sterilized milk. The available fat content was 3.1+/-0.4g/dL (mean +/- SE) in fresh human milk, 3.1+/-0.4g/dL in pasteurized human milk, and 2.7+/-0.3g/dL (P < 0.001 vs. fresh) in sterilized human milk because of formation of a surface skin and fat adherence to the vial wall after sterilization. The fatty acid composition of 10 saturated, 10 monounsaturated, and 10 polyunsaturated fatty acids of both the n6 and n3 series was not affected by pasteurization. In sterilized milk there was a slight decrease of linoleic acid (C18:2n6; -0.7% vs. fresh; P = 0.006) and arachidonic acid (C20:4n6; -2.5%; P = 0.045). Pasteurization and sterilization do not affect total fat content of human milk, but sterilization may reduce available fat content by >10%. Fatty acid composition of human milk is not changed by pasteurization, but is slightly changed by sterilization.

Arachidonic Acid↗
PubMed1995

A review of safety, efficacy, pros and cons, and issues of puerperal tubal sterilization--an update.

This review focuses on the safety, efficacy, pros and cons of tubal sterilization procedures performed during the puerperium period while the woman is still in hospital. Findings from four previous reviews are synthesized, and the results published in more recent literature are evaluated. The review finds that tubal sterilization performed while the woman is still on the delivery table, or during a woman's early puerperium while she remains hospitalized, is operationally easy and medically safe, and does not adversely affect lactation. However, reported pregnancy rates are generally higher in puerperal tubal sterilization than in interval sterilization, especially when the mechanical tubal occlusion technique is used. The Pomeroy method, and its modifications via minilaparotomy, is highly recommendable. On the other hand, electrocoagulation via laparoscopy is associated with high efficacy, but a potentially increased risk of complications and difficulties in tubal reversal. Tubal sterilizations can be easily and safely performed at cesarean delivery in selected cases. Tubal sterilization performed during puerperium has a number of advantages over short-acting contraceptive methods, which require strict compliance, for postpartum use. However, candidates for puerperal tubal sterilization need to be carefully screened and counseled, since post-sterilization regret is more likely to occur. Unsettled issues for puerperal tubal sterilization and a number of practical problems that need to be addressed before initiation of a puerperal tubal sterilization program in a maternity clinic/hospital are discussed.

Female↗
PubMed1982

Interval sterilizations. A substitute for postpartum procedures, an example from Southeast Brazil.

From December 1979 to February 1980, data were collected on access to postpartum sterilization for all obstetric patients at a large maternity hospital in Campinas, Brazil. Of the 827 women wanting no additional children and having knowledge of sterilization, 481 (58%) reported that they wanted to be sterilized. Of these women, 226 (47%) were sterilized postpartum. One year following their deliveries, follow-up forms were administered to the women desiring sterilization, but who had not been sterilized postpartum, to determine if they had been sterilized over the course of the year. Only 13% of the women had been sterilized, but almost 75% of the women not sterilized said they were still interested in getting sterilized. Of the women interviewed, 18% either had become pregnant again since the initial survey or were currently pregnant.

Adult↗
PubMed2001

Low-temperature sterilization using gas plasmas: a review of the experiments and an analysis of the inactivation mechanisms.

Utilizing an ionized gas (plasma) to achieve sterilization is an alternative to conventional sterilization means as far as sterilization of heat-sensitive materials and innocuity of sterilizing agents are concerned. The literature on plasma sterilization is reviewed. A major issue of plasma sterilization is the respective roles of UV photons and reactive species such as atomic and radicals. Insight into this matter is obtained by analyzing the survival curves of microorganisms. In contrast to classical sterilization where such plots show a unique straight line, plasma sterilization yields survival diagrams with two or three different linear segments. Three basic mechanisms are involved in the plasma inactivation of microorganisms: (A) direct destruction by UV irradiation of the genetic material of microorganisms; (B) erosion of the microorganisms atom by atom, through intrinsic photodesorption by UV irradiation to form volatile compounds combining atoms intrinsic to the microorganisms; (C) erosion of the microorganisms, atom by atom, through etching to form volatile compounds as a result of slow combustion using oxygen atoms or radicals emanating from the plasma. In some cases, etching is further activated by UV photons, increasing the elimination rate of microorganisms. These mechanisms make plasma sterilization totally different from classical sterilization techniques and suggest its use to inactivate nonconventional infectious agents such as the abnormal prions.

Bacillus subtilis↗
PubMed2000

Fracture and fatigue properties of acrylic bone cement: the effects of mixing method, sterilization treatment, and molecular weight.

The purpose of this study was to characterize the relative and combined effects of sterilization, molecular weight, and mixing method on the fracture and fatigue performance of acrylic bone cement. Palacos R brand bone cement powder was sterilized using ethylene oxide gas (EtO) or gamma irradiation. Nonsterile material was used as a control. Molecular weights of the bone-cement powders and cured cements were measured using gel permeation chromatography. Hand and vacuum mixing were employed to mold single edge-notched bend specimens for fracture toughness testing. Molded dog-bone specimens were used for fatigue tests. Electron microscopy was used to study fracture mechanisms. Analysis of variance and Student t-tests were used to compare fracture and fatigue performance between sterilization and mixing groups. Our results indicate that vacuum mixing improved significantly the fracture and fatigue resistance (P<.05, P<.07) over hand mixing in radiation-sterilized and EtO-sterilized groups. In vacuum-mixed cement, the degradation in molecular weight resulting from gamma irradiation decreased fracture resistance significantly when compared with EtO sterilization and control (P<.05). A corresponding decrease in fatigue resistance was observed in the cement that was degraded severely by a radiation dose of 10 MRad (P<.05). In contrast, EtO sterilization did not result in a significantly different fracture resistance when compared with unsterilized controls for vacuum-mixed cement (P>.1). For hand-mixed cement, fracture and fatigue resistance appeared to be independent of sterilization method. This independence is believed to be the result of higher porosity that compromised the mechanical properties and obscures any effect of sterilization. Our results indicate that a combination of nonionizing sterilization and vacuum mixing resulted in the best mechanical performance and is most likely to contribute to enhanced longevity in vivo.

Animals↗