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991.
Isolation and characterization of a beta-D-glucuronidase-producing strain of Escherichia coli serotype O157:H7 in the United States. 总被引:2,自引:1,他引:2 下载免费PDF全文
P S Hayes K Blom P Feng J Lewis N A Strockbine B Swaminathan 《Journal of clinical microbiology》1995,33(12):3347-3348
A phenotypic variant of Escherichia coli serotype O157:H7 (G5101) was isolated from a patient with bloody diarrhea. Strain G5101 does not ferment sorbitol but is beta-D-glucuronidase and urease positive. Serotyping and colony hybridization using a serotype-specific DNA probe confirmed that the isolate was O157:H7. G5101 produces Shiga-like toxins I and II and contains an eae gene that is highly conserved in the O157:H7 serotype. This strain would have been missed by laboratories that screen for the sorbitol-negative, beta-D-glucuronidase-negative phenotype in isolating E. coli O157:H7 from clinical and food specimens. 相似文献
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994.
Predictive value of the results of a first in-vitro fertilization cycle on the outcome of subsequent cycles 总被引:4,自引:8,他引:4
This study examines the relationship between the first cycle of in- vitro
fertilization (IVF) and subsequent cycles. The results of all IVF cycles
conducted at The Hammersmith Hospital or The Royal Masonic Hospital between
1988 and 1995 were studied including those cycles where egg recovery was
abandoned due to poor ovarian response. All patients underwent a
standardized treatment protocol. Of those women who achieved a clinical
pregnancy during their first IVF attempt, 33% achieved a pregnancy during
their second cycle, statistically significantly different from the 24% of
patients conceiving during a second cycle who had failed to conceive during
their first. 36% of those who achieved a biochemical pregnancy in their
first cycle became pregnant in their second. Age was an important factor in
the success of IVF treatment, with pregnancy rates of 48% in the 20-25 year
age group falling to 8% in those aged > or =41 years. Cumulative
pregnancy rates were 26% after one cycle, increasing to 43% after two
cycles and reached 80% after seven cycles. A previous pregnancy
significantly improved a couple's probability of conception in a later IVF
cycle. Overall pregnancy rates per cycle were constant for the first three
attempts. Cumulative pregnancy rates continued to rise to 72% after six
cycles. Thus the more cycles a couple undergo (up to six) the greater their
chance of a pregnancy.
相似文献
995.
996.
The TWIST gene maps to 7p21 and mutations in the gene have been reported in
the Saethre-Chotzen form of craniosynostosis. The position of the
Saethre-Chotzen gene has previously been refined by FISH analysis of four
patients carrying balanced translocations involving 7p21 which suggested
that it was located between D7S488 and D7S503. We report here that the
breakpoints in four translocation patients do not interrupt the coding
sequence of the TWIST gene and thus most likely act through a positional
effect. Twelve Saethre-Chotzen cases were found to have TWIST mutations.
Four of these families had been used as part of the linkage study of the
Saethre-Chotzen locus. The mutations detected included missense and
nonsense mutations and three cases of a 21 bp duplication. Although
phenotypically diagnosed as having Saethre- Chotzen syndrome, three
families were found to have a pro250arg mutation of FGFR3.
相似文献
997.
Extracellular matrix improves survival of both stored and fresh human primordial and primary ovarian follicles in long-term culture 总被引:10,自引:13,他引:10
Hovatta O; Silye R; Abir R; Krausz T; Winston RM 《Human reproduction (Oxford, England)》1997,12(5):1032-1036
Ovarian cortical tissue was obtained during gynaecological operations by
biopsy or after oophorectomy from 20 women aged 25-42 years. It was placed
in organ culture, either fresh or following thawing after cryopreservation,
for 1-4 months. The tissue was cut in slices 0.1-0.3 mm in diameter and
transferred to 12 mm inserts in 24-well culture plates. These slices were
cultured for 4-21 days in either alpha minimum essential medium (alpha-MEM)
or Earle's balanced salt solution with added pyruvate. Both media were
supplemented with 10% human serum, insulin, gonadotrophins and antibiotics.
Half of the inserts were precoated with extracellular matrix (Matrigel).
Histological samples revealed that there were viable, non-atretic,
primordial, primary and secondary follicles in all the cultures. Mitoses
were seen in the granulosa cells of the secondary follicles. Although the
proportion of atretic follicles increased during culture, non-atretic
follicles were still present after 21 days. After 4-11 days the proportion
of viable follicles was significantly higher when cultured in Earle's
solution supplemented with pyruvate, than when cultured in MEM (77 versus
38%, P < 0.001). In cultures with extracellular matrix the proportion of
viable follicles was significantly higher after 10-15 days than it was
without matrix (85 versus 19%, P < 0.001). Culture after thawing frozen
ovarian tissue did not affect the density or the proportion of the viable
follicles. Two-thirds of follicles in cryopreserved tissue were viable
after 10-15 days in culture. The results indicate that it is possible to
culture human primary and primordial follicles in vitro, and follicles in
cryopreserved tissue are viable.
相似文献
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