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1.
2.
Direct evidence for the involvement of carbohydrate sequences in human sperm-zona pellucida binding 总被引:2,自引:0,他引:2
Several lines of evidence indicate that mammalian fertilization is
initiated via a binding process that is dependent upon the recognition of
oligosaccharide sequences associated with zona pellucida (ZP)
glycoproteins. Here, specific chemical and enzymatic methods were employed
to modify human ZP and to test their effects on sperm binding in the
hemizona assay system (HZA). Periodate oxidation of human ZP under very
mild conditions (10 min, 0 degrees C, 1 mM sodium m- periodate) that
attacks only terminal sialic acid resulted in a 30% loss of human sperm
binding in the HZA [hemizona index (HZI) = 70.2 +/- 10.9, n = 22; P <
0.05]. Periodate oxidation under mild conditions (1 h, 23 degrees C, 10 mM
sodium m-periodate) caused a 40% decrease in binding (HZI = 60.8 +/- 10.3;
n = 24; P< 0.01). Treatment of human ZP with neuraminidase caused a
substantial increase in sperm binding to human ZP (HZI = 297 +/- 45, n =
22; P < 0.01). These findings indicate that there are sialic acid
dependent binding sites coexisting with binding sites that are obscured by
sialic acid. To determine the periodate sensitivity of these obscured
sites, hemizona were first digested with neuraminidase and subsequently
subjected to mild periodate oxidation. The combined enzymatic and chemical
treatments caused a 79% decrease in sperm binding compared to control
hemizona (HZI = 20.7 +/- 4.4, n = 16; P < 0.001). Human sperm-ZP
interaction was also increased by digestion of human ZP with
endo-beta-galactosidase (HZI = 710 +/- 232, n = 14; P < 0.01),
indicating that potential binding sites for spermatozoa are also obscured
by lactosaminoglycan sequences. These studies support a definitive role for
the involvement of ZP-associated glycans in the binding of human
spermatozoa to oocytes.
相似文献
3.
4.
Urinary pharmacokinetics of betalains following consumption of red beet juice in healthy humans. 总被引:1,自引:0,他引:1
Thomas Frank Florian Conrad Stintzing Reinhold Carle Irmgard Bitsch Daniela Quaas Gabriele Strass Roland Bitsch Michael Netzel 《Pharmacological research》2005,52(4):290-297
The aim of the present pilot study was to characterise the renal elimination of betalains after consumption of red beet juice (RBJ). Six healthy, non-smoking female volunteers were given a single oral dose of either 500 mL of a commercial RBJ containing 362.7 mg of betalains and 500 mL of tap water, respectively, in a sequential manner. Urine was collected in intervals up to 24 h post-dose. Renal excretion of betalains was determined spectrophotometrically and quantified as betanin-equivalents. In addition, the identity of individual compounds was confirmed by HPLC coupled with diode-array detection and positive ion electrospray mass spectrometry, respectively. The amount (mean+/-S.D.) of intact betalains (betanin and isobetanin) recovered in urine was 1001+/-273 microg corresponding to 0.28+/-0.08% of the administered dose. Maximum excretion rates were observed after a median tmax,R of 3.0 h (range 2.5-8.0 h) amounting to 91.7+/-30.1 microg/h. The terminal elimination rate constant (lambdaz) and the corresponding half-life were 0.097+/-0.021 h(-1) and 7.43+/-1.47 h, respectively. Using the lambdaz estimates obtained the expected total betalain amount excreted in urine was 1228+/-291 microg. Based on the results obtained it is assumed that either the bioavailability of the betalains is low or that renal clearance is a minor route of systemic elimination for these compounds. The urinary excretion rates of unmetabolised betalains were fast and appeared to be monoexponential suggesting a one-compartment model. In order to get a more complete picture of the pharmacokinetics and health-promoting properties of red beet betalains, quantitative data on betalain bioavailability should include measurements of unchanged compounds and their corresponding metabolites in plasma, urine and bile. 相似文献
5.
Electroconvulsive therapy (ECT) is commonly used in the practice of geriatric psychiatry. Although it has been found to be both safe and effective, one of the most common complications associated with ECT is falls. A logistic regression model was created to identify independent risk factors for falls in the elderly. Two risk factors were identified: the number of ECT treatments and the diagnosis of Parkinson disease. Further studies are needed to develop strategies aimed at reducing the number of falls. In the meantime, clinicians need to be aware that falls represent an important complication associated with ECT. 相似文献
6.
7.
Cardiac troponin I as prognostic marker in heart failure patients discharged from emergency department 总被引:1,自引:0,他引:1
Despite evidence that cardiac troponin I (cTnI) identifies patients with advanced heart failure (HF) at risk of death, data
on heterogeneous HF populations are scarce. Our purpose was to verify and analyze the prognostic role of cTnI in acute HF
patients admitted to the emergency department. This was an observational longitudinal prospective study carried out in an
urban hospital. We studied 99 patients discharged from the department between March and December 2002 with a HF diagnosis
and samples of cTnI. Patients with acute coronary syndromes, myocarditis or renal failure were excluded. The main outcome
was death from any cause. The detection level of the cTnI assay was 0.05 ng/ml. cTnI was detected in 45.5% of HF patients.
These patients had a higher NYHA class (P < 0.001) at initial presentation and longer hospitalization (P = 0.004) than cTnI-negative patients. Nineteen deaths occurred during the study: 17 for HF and 2 for acute coronary syndrome.
Finally, detectable cTnI was associated with increased mortality risk (RR 4.7; 95% CI 1.3–17.1; P = 0.021) also after adjustment for other adverse prognosis factors (age, NYHA class and presence of relapses). Our HF cTnI-positive
patients had a worse clinical presentation and longer hospitalization. cTnI is a significant independent predictor of death
and of longer hospitalization. It could be used for the early identification of HF patients at an increased risk of death
in the long term, and of longer hospitalization. Thus, cTnI can aid decision-making and clinical management in the emergency
department.
A short abstract of the paper was presented at the A.C.E.P. Scientific Assembly-Research Forum in Boston U.S.A. October 2003. 相似文献
8.
Systemic allergic contact dermatitis caused by methyl aminolaevulinate in a patient with keratosis–ichthyosis–deafness syndrome 下载免费PDF全文
9.
Chi DX Yan GZ Wang WX Lin LM Zhang GF Shi Y 《Journal of medical engineering & technology》2013,37(5):233-237
Manometry of the alimentary tract is a valuable and widely used means to evaluate and diagnose the function of the alimentary tract. However, the measurement can be inconvenient due to the invasive method used, and the many factors affecting results. Research on colonic pressure data is even more insufficient. This paper deals with colonic pressure data via an improved method ensuring that pressure data of the whole colon is available. The data is analysed based on the learning vector quantization (LVQ) method. Testing results show that this method distinguishes the normal data and the abnormal data, consistently with the original diagnoses. This method can serve as an assistant diagnosis of colonic motility and contributes to further research on colonic motility based on pressure data. 相似文献
10.
Arellano FM Wentworth CE Arana A Fernández C Paul CF 《The Journal of investigative dermatology》2007,127(4):808-816
Systemic use of immunosuppressant agents increases the risk of lymphoma in transplantation. We performed a nested case-control study in the PharMetrics database to evaluate the association between topical immunosuppressants and lymphoma in a cohort of patients with atopic dermatitis. We identified cases of lymphoma and randomly selected four controls for each case, matched by length of follow-up. We used conditional logistic regression to calculate odds ratio (OR) and 95% confidence intervals (CIs) of the association between topical immunosuppressants and lymphoma. Two hundred and ninety-four cases of lymphoma occurred in 293,253 patients, 81 in patients younger than 20 years. The adjusted analysis yielded the following OR (95%CI) for: severity (OR 2.4; 95% CI 1.5-3.8), oral steroids 1.5 (1.0-2.4), "super potent" topical steroids 1.2 (0.8-1.8) , "low potency" topical steroids OR 1.1 (0.7-1.6); pimecrolimus 0.8(0.4-1.6), tacrolimus OR 0.8 (0.4-1.7), and concomitant topical steroids, pimecrolimus, and tacrolimus 1.0 (0.3-4.1). We did not find an increased risk of lymphoma in patients treated with topical calcineurin inhibitors. It is difficult to disentangle the effects of severity of disease on outcome versus the true effects of drugs. However, in the adjusted analysis, severity of AD was the main factor associated with an increased risk of lymphoma. 相似文献