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Laparoscopic sterilization of Sardinia donkeys using an endoscopic stapler.

OBJECTIVE: To describe a laparoscopic technique for sterilization of the male donkey using an endoscopic linear stapler (ELS). STUDY DESIGN: Clinical report. ANIMALS: Male Sardinia donkeys (n=6), aged 24-36 months. METHODS: Laparoscopic sterilization was performed under standing sedation or recumbent under general anesthesia. An endoscopic linear stapler was used to transect, and control hemorrhage of, the spermatic cord. Serum testosterone concentrations were measured preoperatively and at 3, 6, and 12 months after sterilization. One testis from each of 2 donkeys was collected at 12 months for histologic examination. RESULTS: Sterilization was successfully achieved. The only minor intraoperative complication experienced was hemorrhage from 1 spermatic cord stump, which was re-stapled. No other major short- or long-term complications occurred. Serum testosterone concentrations were < 15 ng/dL at 3, 6, and 12 months after surgery in all donkeys. Testicular atrophy without evidence of revascularization was observed in the 2 testes examined histologically. CONCLUSIONS: Sterilization of descended testes by intraabdominal laparoscopic transection of the spermatic cord is a simple practical method, with minimal intraoperative or postoperative complications. Testicular revascularization did not occur. CLINICAL RELEVANCE: Laparoscopic sterilization in donkey can be performed using an endoscopic linear stapler as an alternative to scrotal castration.

Animals↗

Improving the biological control of leafminers (Diptera: Agromyzidae) using the sterile insect technique.

The leafminer Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) is a worldwide pest of ornamental and vegetable crops. The most promising nonchemical approach for controlling Liriomyza leafminers in greenhouses is regular releases of the parasitoid Diglyphus isaea (Walker) (Hymenoptera: Eulophidae). In the current study, we examine the hypothesis that the use of D. isaea for biological control of leafminers in greenhouse crops may be more practical and efficient when supplemented with additional control strategies, such as the sterile insect technique (SIT). In small cages, our SIT experiments suggest that release of sterile L. trifolii males in three sterile-to-fertile male ratios (3:1, 5:1, and 10:1) can significantly reduce the numbers of the pest offspring. In large cage experiments, when both parasitoids and sterile males were released weekly, the combined methods significantly reduced mine production and the adult leafminer population size. Moreover, a synergistic interaction effect between these two methods was found, and a model based on our observed data predicts that because of this effect, only the use of both methods can eradicate the pest population. Our study indicates that an integrated pest management approach that combines the augmentative release of the parasitoid D. isaea together with sterile leafminer males is more efficient than the use of either method alone. In addition, our results validate previous theoretical models and demonstrate synergistic control with releases of parasitoids and sterile insects.

Animals↗

The search for new sterilizing anti-tuberculosis drugs.

To be of use in the control of tuberculosis, any new drug must be capable of shortening the duration of treatment by accelerating sterilizing activity, that is the rate at which Mycobacterium tuberculosis is killed in the lesions. The most difficult to kill are the extra-cellular bacilli in cavities. Persistence during therapy arises because there is a proportion of slowly metabolising bacilli (persisters) in the cavitary bacterial population at the start of treatment. Bacterial growth is slowed by low oxygen tension, quorum sensing and old age, but probably not by cellular immunity, since there are few professional phagocytic cells in cavities. The degree of phenotypic resistance to the bactericidal action of drugs can go through several stages: (i) the non-replicating stages 1 and 2 of micro-aerophilic adaptation, described by Wayne; (ii) a "tolerant" population that survives exposure to high rifampicin concentrations and is capable of growth in liquid medium but not on solid medium; and (iii) a population found in the sterile state of Cornell model mice which cannot grow initially in either liquid or solid medium but will eventually cause re-activation of tuberculosis. In all of these stages the bacilli are phenotypically resistant; there is no selection for genomic drug resistance. Rifampicin and pyrazinamide are the two drugs largely responsible for sterilizing activity during current treatment. Pyrazinamide is unique amongst anti-tuberculosis drugs in having no genomic site of action and having greater bactericidal activity as bacillary metabolism slows down; it is remarkably effective in human disease. The development of a new drug with a similar mode of activity might be very fruitful, especially if there were no need for an acid environment. Current methods advocated for drug development pass through a number of complex stages: choice of a genomic target, development of an in vitro assay, high throughput screening and identification of lead compounds, often with scaling up of synthesis of the molecule and preliminary studies of toxicity and animal pharmacology before tests are done for sterilizing activity. If the drug is not good at sterilizing, all of this initial work will be largely wasted as it would only have a very limited role in the treatment of MDR disease. One of the most important steps necessary is the development of rapid and simple tests to screen for sterilizing activity. Of tests currently available, none of those employing mice seem adequate, though a screen using a streptomycin dependent Mycobacterium tuberculosis seems the most hopeful. A set of in vitro tests is described. There is an urgent need to develop these tests further since the factors slowing growth are closer to those in tuberculous cavities than in mouse models. They have the advantages of simplicity and require only small amounts of a new molecule.

Animals↗

Estimation of the proportions of dogs and cats that are surgically sterilized.

OBJECTIVE: To determine an estimate of the proportions of dogs and cats in Texas that are surgically sterilized and whether those proportions differed according to species and sex of the animal, level of responsibility of the owner, or geographic location. DESIGN: Cross-sectional study. ANIMALS: 43,831 dogs and cats > or = 6 months old. PROCEDURE: Information on sterilization rates was provided by 14 licensing agencies and 16 animal shelters in diverse regions of Texas. Univariate and multivariate analyses were used to compare sterilization rates among subpopulations of animals (dogs vs cats, males vs females, sheltered vs licensed, rural vs urban location). RESULTS: Overall, 12,893 (29.4%) of the animals (26.9% of dogs and 32.6% of cats) were sterilized. Proportions of animals sterilized were significantly different among subpopulations. CONCLUSIONS AND CLINICAL RELEVANCE: Although the cause of pet overpopulation is multifaceted, failure of owners to spay and castrate their animals is a major contributing factor. Significant differences in sterilization rates among subpopulations of dogs and cats suggest that organizations encouraging spaying and castration should use motivational techniques specific for the pet owners they are targeting.

Animals↗

[Molecular mapping of the S-a locus for F1 pollen sterility in cultivated rice (Oryza sativa L.)].

F1 pollen sterility in cultivated rice (Oryza sativa L.) was found to be caused by at least six loci of F1 pollen sterility genes. At the S-a locus, one of the six loci for F1 pollen sterility, the allelic interaction of S-ai and S-aj causes the male gametes carrying S-aj allele abortive. To map the S-a locus, Taichung 65(T65), a Keng (japonica) variety with S-aj/S-aj, its isogenic F1 sterile line TISL4 with S-ai/S-ai from Chin-tsao, a Hsien (indica) variety, and the F2 population from cross T65 x TISL4 were used as materials. The polymorphism between T65 and TISL4 detected by RFLP and RAPD analysis was less than 1%. This result indicated that short segments from Chin-tsao were introgressed into the isogenic F1 sterile line, since the TISL4 was developed by repeatedly backcrossing for thirteen times. By linkage analysis of S-a and the marker loci, the S-a locus was mapped on chromosome 1. The genetic distances between S-a and RFLP markers CDO548 and RG146 are 6.4 cM and 7.2 cM respectively, and those between S-a and RAPD markers O11-1000 and Y13-500 are 6.8 cM and 11.2 cM respectively. The mapping of the S-a locus is an important step towards marker-aided selection for overcoming the hybrid sterility in rice.

Chromosome Mapping↗

[Influence of genetic background of photoperiodic response on expression of short photoperiod sensitive male sterility in rice].

The photoperiodic response of F1 and its parents was analyzed, and the photoperiodic response and short photoperiod sensitive male sterility of F2 progenies were studied in this paper. The results showed that the strong response was dominant over the weak response to photoperiod. The photoperiodic response of plants with short photoperiod sensitive male sterility in F2 was above medial degree(the rate of heading acceleration > 15%). Photoperiodic response showed a positive correlation with short photoperiod sensitive male sterility. The main sterility genes of Yid1s and Yid2s were allelism. It can be inferred that the short photoperiod sensitive male sterile gene might be expressed upon the presence of the photoperiodic response genes, and that the short photoperiod sensitive male sterility of plants with the same genes could differ in their reproductive expressions, not because of the changes of the genes, but the difference in genetic backgrounds of photoperiodic response.

Fertility↗

Principles of area-wide integrated tsetse fly control using the sterile insect technique.

The tsetse fly and the disease trypanosomosis it transmits, is one of the most severe medical and veterinary problems in Africa, infecting around 50,000 people every year and preventing the development of sustainable and productive agricultural systems. The most efficient way to contain the disease is by the management of entire populations of the vector (area-wide approach) using a combination of several control methods in an integrated pest management campaign. A very powerful method for integration in these programmes as a final eradication component is the sterile insect technique (SIT). The technique relies on the rearing of the target insect in large numbers in specialised production centres, the sterilisation with ionising radiation of one of the sexes and the sustained sequential release of the sterilised insects over the target area. Contrary to conventional control methods, the sterile insect technique becomes more efficient with decreasing density of the target population. Hence, the technique fits well within the concept of integrated pest management, as its complementary use in a phased approach with other suppression techniques, results in maximum efficiency. The five main prerequisites required to use the sterile insect technique against a target insect have been achieved for tsetse flies: 1. adequate information on the ecology of the insect is available, 2. the mass-production of the target insect is economically feasible, 3. efficient suppression techniques are available to reduce the population density of the target insect, 4. sufficient sterile males are available for release and their competitiveness is optimal, 5. the gamma treated sperm is competitive with the wild sperm. This paper gives a detailed review of the five implementation phases of the sterile insect technique based area-wide integrated pest management campaign against Glossina austeni on the island of Unguja, Zanzibar. The potential future prospects and requirements of using the sterile insect technique against tsetse populations are likewise presented.

Africa↗

Cytological observation of two environmental genic male-sterile lines of rice.

We report here two environmental genic male-sterilities (EGMS) in rice. These two EGMS rice lines, thermo-sensitive genic male-sterility (TGMS) and photoperiod-sensitive genic male-sterility (PGMS), are controlled by temperature and photoperiod, respectively, in determining their male-sterility. Male-sterility of the TGMS and PGMS was found to be induced when they were grown at 32 degrees C/26 degrees C (day/night) with 14 h daylight, while they were fertile at 26 degrees C/20 degrees C (day/night) with 10 h daylight in a growth chamber. We also examined their anther structures under a light microscope. The light microscopic observation revealed that the EGMS lines showed a complete pollen abortion at the sterile growth condition while they produced normal fertile pollens at the fertile growth condition.

Fertility↗

[Genetics study on photo- and thermo-sensitive genic male sterility of indica rice (O. satival L.)].

The sterility segregation and its genetic patterns of indica P(T)GMS rice were analyzed mainly based on the investigation of bagged seed-set of individuals in reciprocal F2 population from the crosses between P(T)GMS lines of different origin and typical indica conventional varieties of different ecotype under long day-length and high temperature condition by using the software of the maximum likelihood method. The results showed that the sterility of Annong S-1, Hengnong S-1, and W6154S, of which the sterility alteration was mainly induced by temperature fluctuation, was controlled by one major recessive gene. But the sterility of W7415S was controlled by more than two major recessive genes. Apart from the major recessive gene, there was a group of polygenes in controlling of the sterility segregation in F2 population. Moreover, the polygenic variance was different from line to line. It implied that the polygenes of W6154S or W7415S was far more complicated than that of Annong S-1 and Hengnong S-1 according to the maximum likelihood method. All the conventional indica varieties of different ecotypes possessed the major dominant fertility genes. Meanwhile, the genetic background in different ecotype conventional varieties, the essentiality of which lies in the existence of polygenes, was different and influenced the major gene expression deeply. It was also indicated that genetic background of middle-season variety Nanjing 11 was more complicated than that of early-season variety Erjiuqing and late-season variety GER-1 as well. Finally, the differences of drift in critical temperature inducing male sterility of P(T)GMS lines (for short term DCT) and the strategy of breeding practically usable P(T)GMS line with slighter DCT were discussed in the paper.

Crosses, Genetic↗

[Mapping of two fertility-restoring gene for WA cytoplasmic male sterility in minghui63 using SSR markers].

F2 population derived from Shanyou63, F1 hybrid developed from the cross Zhenshan97 A/Zhenshan97B, was used in this study. Fertile bulk was constructed by polling equal amount of 15 highly fertile lines. Sterile bulk was obtained by pooling equal amount of 15 highly sterile lines. Minghui63 and Zhenshan97A, parents of Shanyou63, were analyzed with 302 pairs of SSR primers. 244 pairs of primers gave amplification products, of which 58 pairs of primers on 12 different chromosomes showed polymorphism between the two parents with polymorphic frequency up to 23.77%. Gene bulks were further assayed with the 5 pairs of primers. RM1 on chromosome 1 and RM258, RM304 on chromosome 10 was found to be polymorphic between the two gene bulks. In theory, there should be no difference detected between the two gene bulks except for the target traits governed by fertility-restoring genes. RM1, RM258 and RM304 were probably related to the restorer genes. Ten highly fertile and ten highly sterile lines were selected from F2 population of Shanyou63 to screen the gene bulks. The results showed that specific bands of Minghui63 were detected in all ten highly fertile lines while not observed in all the sterile lines. It indicated that the three SSR markers might be linked to fertility-restoring genes. Dominant lines were not selected due to their inalbility to distinguish recombinant lines from non-recombinant lines. Pure recessive lines were chosen to conduct mapping analysis. A total of 53 highly sterile lines were selected from 900 lines of Shanyou63 F2 population to estimate the genetic distance between three SSR markers and fertility-restoring genes respectively. The results demonstrated that recombination occurred in 2, 3, lines with RM1 and RM258 while no one with RM304. Using MAPMAKER/EXP 3.0, the genetic distance between RM1, RM258, RM304 and the related restorer genes were calculated as 1.9, 2.9 and 0.0 cM, respectively. It is possible that the fertility restoring gene(s) on chromosome 10 for three different types of cytoplasmic male sterility(WA, BT and HL) are of the same, or belong to a gene family.

Chromosome Mapping↗

[Genetic mapping of the intergenomic translocated "taigu" genic sterility gene (Ms2)].

The "Taigu" genic sterility gene Ms2 located on the short arm of the 4D chromosome of common wheat (AABBDD) originally incorporated into hexoploid triticale (AABBRR) and durum wheat (AABB) through intergenomic translocation in distant hybridization was introduced back into the genomes of common wheat. The dominant male sterility was expressed normally in the new "Taigu" genic sterile wheat carrying the intergenomically translocated Ms2, and the female fertility mechanism in its male sterile plants was normal as well. Observation of the chromosome configuration at meiosis of pollen mother cells (PMC) of the young ears of the sterile plants showed that they were euploid plants (2n = 42). No configurations different from those of the "Taigu" genic sterility gene located at the original locus were noticed of the Ms2 intergenomically translocated back into the common wheat. In systematic test crosses with marker genes the intergenomically translocated gene Ms2 was found to be linked with the dominant dwarf marker in common wheat Rht3 and, consequently, remapped and located on the short arm of the 4B chromosome of common wheat with a distance of 9.7 cM from Rht3. The new locus was designated as Ms2 (4BS). Discussions are given of the fate of Ms2 during translocation in the hexoploid triticale, the exchange of the names for 4A and 4B chromosomes in common wheat and the possible exploitation of the new locus Ms2 (4BS), and the following speculations are made: (a) In genic genes of allopolyploid organisms the donor chromosomes tend to be intergenomically translocated to their physiologically and evolutionarily close chromosomes with the same order number and the same arm; (b) it is confirmed that the 7th International Conference of Wheat Genetics was right to exchange the names between chromosomes 4A and 4B of common wheat in 1988; and (c) as a new genetic marker and a breeding tool for all the chromosome B-carrying species in the tribe of Triticeae, Ms2(4BS) may have wide application in building and expanding the gene pool of germplasm resources of various species of wheat.

Chromosome Mapping↗

The impact of relapsing sterile icodextrin-associated peritonitis on peritoneal dialysis outcome.

BACKGROUND: The emphasis in peritoneal dialysis (PD) has shifted from a therapy with short-term goals to one of prolonging the life of the peritoneal membrane. Icodextrin (ICO), a starch-derived glucose polymer that is metabolized to maltose, is a valuable osmotic agent in the treatment of PD patients with defective ultrafiltration. However, ICO can cause sterile peritonitis. The manufacturer has recently withdrawn a series of batches of ICO solutions due to evidence of bacterial contamination (a bacterial cell wall breakdown, peptidoglycan). Some cases have been reported of culture-negative ICO-associated peritonitis which relapse on re-challenge. METHODS: We started to use ICO in chronic uremic PD patients in 1997. Ten patients out of 82 treated in our PD unit were exposed to ICO from 1997-2002. We registered 50 peritonitis episodes in this period: 34 were bacterial and 16 culture-negative. Among the 16 episodes of sterile peritonitis, 6 occurred in patients treated with ICO. Four of the 6 ICO treated patients experienced relapsing culture-negative episodes of peritonitis. We reviewed the records of the four patients. RESULTS: The first episodes of sterile ICO-associated peritonitis occurred between February-May 2002. These were clinically very mild and the only sign was abdominal discomfort and a cloudy dialysate containing a number of WBC/mm(3) ranging from 500-800. Cultures were negative. All the ICO solutions were from the batches withdrawn by the manufacturer. ICO (with new batches of solution) was re-introduced in all patients some weeks later to improve ultrafiltration. A new episode of sterile peritonitis occurred with the same characteristics as described above. Three of the four patients were re-challenged with new batches of ICO solution and again sterile peritonitis occurred. One patient was switched directly to hemodialysis (HD); the others were transferred to a program of automated PD including hypertonic glucose solutions. In 8 months all patients were switched to HD because of the failure of ultra-filtration. It is possible that the first episode of sterile peritonitis, associated with the use of an ICO batch suspected of having high peptidoglycan levels could have induced sensitization to ICO, which in turn could have been the cause of the relapse on re-challenge. CONCLUSIONS: The disappointing result of the relapsing culture-negative ICO-associated peritonitis in our patients was the unavoidable switch to HD, due to the inability of the hypertonic glucose solutions to ensure an adequate ultrafiltration. The moral of the story is that the pharmaceutical industry should market products that are more biocompatible and safer for chronic treatments such as PD.

Aged↗

[Hormonal monitoring of the menstrual cycle among sterile women. III].

This paper attempts to assess the value of the dynamical examinations of the concentrations of the ovary hormones progesterone and estradiol in the menstrual cycle. RIA were made on 22 sterile women with the monophasic cycle and 119 sterile women with the biphasic cycle in comparison with 17 women who delivered at least one child without previous treatment (control group). The dynamical RIA were made on all women between the 5th and 26th day of the menstrual cycle. The results of these assays were compared on the 8th, 14th, 15th, 16th, 21st and 25th day of the menstrual cycle. The examinations confirmed a markedly lower concentrations of estradiol throughout all the time of the cycle among sterile women with the monophasic cycle and a little higher concentrations among sterile women with the biphasic cycle. Markedly lower concentrations of progesterone were observed throughout all the time of the cycle among sterile women with the monophasic cycle and a little higher concentrations of it were found among sterile women with the biphasic menstrual cycle.

Estradiol↗

[Isolation, characterization and expression analysis of male sterility gene homology sequence in wheat].

One 134 bp fragment was amplified in anthers of male sterile and fertile wheat using one pair of degenerated primer designed based on the conserved domain of MS2 gene in Arabidopsis thaliana and Oryza sativa, and one 1604 bp male sterility gene homology sequence was extended by in silico cloning based on the 134 bp fragment. The amino acids encoded by the male sterility gene homology sequence include a 200 amino acid conserved domain of male sterility, and this sequence expressed only in wheat male fertile anthers; no expression in male sterile anthers, roots and leaves. This research demonstrated that the cloned male sterile homology sequence is specific to wheat anther development.

Amino Acid Sequence↗

Intraparental gamete competition provides a selective advantage for the development of hybrid sterility via meiotic drive.

Hybrid sterility can have evolutionary significance and varies substantially by taxon, but few models attempt to predict or explain this variability. Hybrid sterility is commonly observed and develops early in isolation, at odds with straightforward models that predict it would develop slowly and rarely be seen. Meiotic drive might explain the rapid development of hybrid sterility, but drive is rarely observed, modifiers are expected to repress it, and no precise testable predictions are available. Here I develop population genetic models for the establishment of meiotic drive based on how it spreads by benefiting carrier gametes competing with noncarrier gametes from the same parent, or intraparental gamete competition. The resulting models predict that meiotic drive can often produce substantial hybrid sterility over time even in the presence of repressors, yet observable drive will be rare. They also make quantitative predictions of the degree of sterility based on observable parameters of reproductive ecology, including frequency of multiple mating, effective dispersal of offspring, and population size. Finally, they suggest explanations for the association of heterochromatin changes with speciation. Experimental evidence is discussed showing that drive alleles at least sometimes contribute to hybrid sterility.

Computer Simulation↗

[Locating maize male sterility gene induced by space flight using microsatellite markers].

Two F2 populations with different kinds of spike derived from maize male sterility materials RP(3)195 (A) x S37 (inbred line) ,which had been sib-bred for many generations,were used for sterility analysis and gene location. There were 138 and 247 plants in the two F2 populations respectively. Among the 326 pairs of microsatellite primers selected,56 were found polymorphic. Linkage analysis of F2 populations with the 56 pairs of primers showed that microsatellite markers bnlg197 and umc1012 were linked with the male sterility gene. The genetic distance between marker bnlgl97 and the male sterility gene in the two different F2 populations were 7 cM and 14.5 cM respectively. The genetic distance between marker umc1012 and the male sterility gene in the 138 plants was 28.5 cM. Thus the male sterility gene was located on chromosome 3L.

Chromosome Mapping↗

Individual-level sterility: a new method of estimation with application to sub-Saharan Africa.

This paper extends work on measures of population proportions sterile to propose a new estimator of an individual woman's age at sterility and consequently her sterility status at given ages. Accuracy and reliability, examined in a simulation study, appear satisfactory. From World Fertility Survey data for five African countries, the proportions sterile by age estimated by the individual measure and by the population estimator are almost identical. Cameroon and Kenya show substantial variation in prevalence and incidence of sterility across ethnic groups and by number of marriages. Unexpectedly, the evidence suggests that sterility increased from 1960 on in Kenya and remained unchanged in Cameroon.

Adolescent↗

Chemosterilization of Culex pipiens fatigans Wiedemann by exposure of aquatic stages. I. Sterilization potential of certain aziridinyl compounds.

The sterile-male technique has been considered to be a promising tool for the control of mosquito populations. Many chemosterilants are known to sterilize insects effectively in the same way as ionizing radiations. The sterilizing activity of 8 alkylating aziridinyl compounds has been assessed on the tropical house-mosquito, Culex pipiens fatigans Wiedemann. The chemosterilants employed for larval and pupal treatments were apholate, metepa, tepa and 5 diaziridinyl alkoxyphosphine oxides. In general, metepa was least toxic to the various life stages of C. p. fatigans during the treatment. Apholate was toxic only in pupal treatments while tepa was less toxic in pupal treatments and more toxic in larval treatments. Diaziridinyl compounds were moderately toxic in both larval and pupal treatments. The tepa and apholate treatments caused certain structural and moulting abnormalities in pupae and adults and also induced abnormalities in eggs and larvae.Among the polyaziridinyl compounds, non-toxic doses of apholate could produce about 100% sterility with larval treatment. Tepa was inferior to apholate, and metepa was least effective in larval treatment. Among the diaziridinyl compounds, the methyl ester was most promising. For pupal treatment, tepa was more effective than apholate and metepa at non-toxic doses, inducing almost complete sterility. The propyl and isopropyl esters of the diaziridinyl compounds also induced very high sterility in pupal treatments.

Animals↗