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991.
van der Put NM; Thomas CM; Eskes TK; Trijbels FJ; Steegers-Theunissen RP; Mariman EC; De Graaf-Hess A; Smeitink JA; Blom HJ 《QJM : monthly journal of the Association of Physicians》1997,90(8):505-510
Folic acid intake reduces the risk of neural tube defects (NTDs). Although
the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase
(MTHFR) gene is a risk factor for NTDs, it only partly explains the
elevated homocysteine levels in mothers of children with NTDs. We measured
vitamin B12, folate and homocysteine in patients with spina bifida (SB),
their parents, and in controls, to investigate which other enzymes of
homocysteine metabolism might be defective. Because homozygosity for the
677C-->T mutation causes decreased plasma folate and increased red-cell
folate (RCF) and plasma homocysteine levels, we excluded individuals
homozygous for that mutation. The remaining SB patients and their parents
still had lowered plasma folate and elevated total homocysteine levels, and
a small subset had decreased vitamin B12 levels. Red-cell folate was the
same in all groups, suggesting that dietary folate intake and its uptake
was normal. Risk of SB was increased at the 25th percentile of plasma
folate and at the 75th percentile of homocysteine values in SB patients and
their parents, and at the 5th and 25th percentiles of vitamin B12 in
mothers with SB- affected offspring. This underlines the functional
importance of homocysteine remethylation to methionine. There was no
correlation between vitamin B12 and homocysteine or RCF. In combination
with the lowered plasma folate (80-90% 5-methyltetrahydrofolate), our data
do not support a major involvement of methionine synthase in the aetiology
of SB. Our data rather favour the involvement of genetic variation at loci
coding for the formation of 5-methyltetrahydrofolate, such as MTHFR,
methylenetetrahydrofolate dehydrogenase or serine hydroxymethyltransferase.
相似文献
992.
Imaging of pregnancy-associated breast cancer 总被引:4,自引:0,他引:4
993.
Acute mesenteric ischemia: diagnosis with contrast-enhanced CT 总被引:34,自引:1,他引:33
994.
T F Smith L A Weed J W Segura G R Pettersen I I Washington JA 《Mayo Clinic proceedings. Mayo Clinic》1975,50(3):105-110
From October 1973 through August 1974, 335 genitourinary tract specimens from patients with urethritis were inoculated into McCoy's cell cultures for the diagnosis of Chlamydia infections. Of the 45 Chlamydia isolates, 42 were recovered when glass vials rather than plastic microtiter plates were used as cell culture vessels. Herpes simplex virus was isolated 15 times. Bacterial overgrowth occurred 42 times; however, in 20 specimens the contamination was not apparent until after the first subculture. This is the first report of the frequency of Chlamydia infections in patients with urethritis in the Midwest and indicates that these organisms have a significant etiologic role in nongonococcal urethritis in this community. 相似文献
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998.
The urinary bladder, obliterated umbilical arteries, and inferior epigastric vessels located within the extraperitoneal space of the anterior abdominal wall indent the anterior parietal peritoneum, forming intraperitoneal paravesical fossae. These are the supravesical space and the medial and lateral inguinal fossae. More posteriorly, the peritoneum covering the bladder is reflected onto the rectum to form the rectovesical space, which is divided by the uterus into an anterior vesicouterine recess and a posterior rectouterine pouch, or cul-de-sac. The cul-de-sac is continuous with the pararectal and ovarian fossae and is bounded posterolaterally by the rectouterine (sacrogenital) folds. These peritoneal compartments form a large potential space for the accumulation of ascites and are separated from the equally large extraperitoneal paravesical spaces by only a thin layer of peritoneum or peritoneum and umbilicovesical fascia. The computed tomographic scans of 100 patients with ascites were reviewed, with particular attention to the differentiation between intraperitoneal and extraperitoneal paravesical collections. The scans of intraperitoneal collections were found to have certain characteristic appearances, including inferior displacement of the distended urinary bladder, visualization of the umbilical folds, and preservation of the preperitoneal fat. 相似文献
999.
Gomori JM; Grossman RI; Shields JA; Augsburger JJ; Joseph PM; DeSimeone D 《Radiology》1986,158(2):443-445
Six freshly enucleated, unfixed human eyes with choroidal melanomas were imaged on a 1.4-T superconducting magnetic resonance (MR) imaging system. Immediately thereafter the eyes were sectioned, and tumor samples were removed for study on a variable-field (0.19-1.4 T) nuclear MR spectroscopy unit. Shorter T1 and T2 relaxation times were observed in those tumors with the greater concentrations of melanin. This is believed to result from the paramagnetic effect of radicals known to exist in melanin. High magnetic field MR imaging can enable one to distinguish between pigmented melanomas; proteinaceous effusions; fresh and subacute hematomas; and nonmelanotic tumors, including amelanotic melanomas; but may not enable melanotic melanoma to be distinguished from fat or amelanotic melanoma from other nonpigmented tumors. 相似文献
1000.
Hydroxyapatite deposition disease 总被引:2,自引:0,他引:2