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排序方式: 共有432条查询结果,搜索用时 15 毫秒
91.
92.
A suitable for analysis of the effect of structural and chemical changes on haemocompatibility of polymers is polyacrylonitrilics (PNA), which, depending on the thermo-processing (temperature, medium), make a number of materials, differing in structure and properties. A comparative analysis of physical and chemical initial properties as well as of thermically processed PNA fibres was made. By the methods of radioisotope and of fluoroscent spectroscopy the kinetics of early stages of adsorption of plasma albumine (AS) and of plasma fibrinogen (FG), the kinetics of desorption of pre-adsorbed plasma albumine in a model solution, and thrombocyte adhesion of the PNA surface were studied. The extreme nature of the irreversability degree in albumine and fibrinogen adsorption, the effective coefficients of the albumine desorption speed, and the number of bound thrombocytes at the temperature increase in thermal processing were found, and better quantitative criteria of haemocompatibility in vitro for PNA, processed thermally in the air. The achieved results can be explained by occurrence of, in a number of studied PNA fibres, an optimum ratio of the dispertion and polar superficial surrounding energy. 相似文献
93.
94.
Aim : Fabry disease is an X-linked inborn error of glycosphingolipid metabolism due to the deficient activity of α-galactosidase A, a lysosomal enzyme. It is a multisystem disorder characterized by progressive renal insufficiency, with added morbidity from cardio- and cerebrovascular involvement. The recent availability of genetically engineered enzyme offers an effective targeted treatment approach, but also emphasizes the need for surrogate markers to delineate organ damage and monitor the efficacy of enzyme replacement therapy (ERT). Methods : Multiple endothelial factors and plasma homocysteine concentrations were investigated in 12 consecutive hemizygous males with classic Fabry disease and 15 controls as part of an exhaustive baseline evaluation prior to ERT. Results : Compared with the controls, plasma concentrations of homocysteine were significantly ( p > 0.01) higher in patients with Fabry disease in the absence of chronic renal failure or vitamin deficiency. Plasma concentrations of vascular cell adhesion molecule-1 were also significantly ( p > 0.05) higher in the patients, and there was a trend for decreased endothelin-1 levels. No difference was found in serum intercellular adhesion molecule-1, plasma P-selectin, serum E-selectin and plasma thrombomodulin between the patients and controls.
Conclusions : The results do not reveal measurable evidence for endothelial and leukocyte activation that could reliably serve as surrogate markers for routine monitoring of the efficacy of ERT in patients with Fabry disease. While the exact origin and clinical significance of hyperhomocysteinaemia in Fabry disease remains to be studied in a larger cohort of patients carefully monitored for their concurrent medications, especially carbamazepine, we suggest that patients may benefit from folic acid or multivitamin therapy to treat this additional vascular risk factor, when present. 相似文献
Conclusions : The results do not reveal measurable evidence for endothelial and leukocyte activation that could reliably serve as surrogate markers for routine monitoring of the efficacy of ERT in patients with Fabry disease. While the exact origin and clinical significance of hyperhomocysteinaemia in Fabry disease remains to be studied in a larger cohort of patients carefully monitored for their concurrent medications, especially carbamazepine, we suggest that patients may benefit from folic acid or multivitamin therapy to treat this additional vascular risk factor, when present. 相似文献
95.
CF Poets VA Stebbens JR Alexander WA Arrowsmith SAW Salfield DP Southall 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(6-7):536-541
Nineteen infants who were graduates from special care baby units underwent two overnight tape recordings of oxygen saturation (SaO2) and breathing movements; one during an upper (n = 12) or lower (n = 7) respiratory tract infection and the other when free of infection. Baseline SaO2 was lower during infection (median 99.6 vs 100%, p less than 0.01), with four patients having values (84.3-95.5%) below the normal lower limit for full-term infants (97%). The median number of apnoeic pauses was also lower during respiratory tract infection (4.7 vs 15.7/h, p less than 0.02). The median number of episodic desaturations (SaO2 less than or equal to 80%) did not change significantly (1.3 vs 1.9/h, p greater than 0.05), with the exception of one patient who had extremely increased values during infection for both apnoeic pauses (63/h) and desaturations (112/h). No infant, however, was considered clinically hypoxaemic. Clinically unsuspected hypoxaemia may thus occur during respiratory tract infection in a proportion of infants graduating from special care baby units. Such hypoxaemia may have potentially deleterious effects. 相似文献
96.
97.
Prevalence and infectivity of hepatitis G virus and its strain variant, the GB agent, in volunteer blood donors in Taiwan 总被引:2,自引:0,他引:2
BACKGROUND: The prevalence of hepatitis G virus (HGV) and its strain variant, the GB agent (GBV-C) is high in non-virus-inactivated plasma products, but, persistent infection in recipients is relatively low. STUDY DESIGN AND METHODS: Stored samples from transfusion donors and recipients in a prospective study of posttransfusion hepatitis were tested for HGV RNA and antibody to the E2 protein (anti-E2). RESULTS: Thirty-two (2.1%) of the 1500 qualified donors were positive for HGV RNA. Twenty-four persons had received a transfusion of blood from one of these 32 viremic donors. Of these 24 recipients, 3 were positive for HGV RNA before transfusion. Of the remaining 21 recipients, 8 became viremic after transfusion, while the other 13 were not infected. Four of the eight infected recipients were persistently positive for HGV RNA, while four became negative in 1 to 3 years. Three of the four patients with HGV clearance seroconverted to anti-E2 positivity. Comparison of the viral titer, viral sequences at E2, storage period of blood donations, and clinical data in the infected and noninfected recipients revealed no significant differences. However, the noninfected recipients seemed to have a higher prevalence of anti-E2 before transfusion. CONCLUSION: The prevalence of HGV viremia in volunteer blood donors in Taiwan is 2.1 percent, and blood from 0.6 percent of them actually causes HGV infection in the recipients. In half of infected recipients, clearance of HGV occurs. Anti-E2 appears in most recipients whose viremia is cleared. 相似文献
98.
Close mapping of the focal non-epidermolytic palmoplantar keratoderma (PPK) locus associated with oesophageal cancer (TOC) 总被引:1,自引:1,他引:1
Kelsell DP; Risk JM; Leigh IM; Stevens HP; Ellis A; Hennies HC; Reis A; Weissenbach J; Bishop DT; Spurr NK; Field JK 《Human molecular genetics》1996,5(6):857-860
Focal non-epidermolytic palmoplantar keratoderma (PPK or palmoplantar
ectodermal dysplasia type III) is associated with oesophageal cancer in
three families: two large pedigrees located in Liverpool, UK and in the
midwestern American states and one smaller family from Germany. In these
families, the PPK is inherited as autosomal dominant and has a late onset,
usually manifesting between 7 and 8 years of age. The disease is
characterised by thickening of the pressure areas of the soles, but is not
restricted to the feet and also presents with oral leukokeratosis and
follicular hyperkeratosis. The disease locus [previously termed the
"tylosis oesophageal cancer gene' (TOC) locus] has been mapped to
17q23-qter by linkage analysis. This region is located telomeric to the
keratin 16 gene, in which mutations have been identified in focal PPK
families who show no increased cancer risk. We describe the close mapping
of this locus to the interval between AFMb054zf9 and D17S1603 using
haplotype analysis of additional Genethon markers in the region and show
that although the American family is unlikely to be related to either of
the other two, the UK and German pedigrees may share a common descent. This
work provides a basis for positional cloning and candidate gene analysis in
order to identify a gene that may be involved in familial oesophageal
cancer.
相似文献
99.
Sperm-induced oocyte activation in the rhesus monkey: nuclear and cytoplasmic changes following intracytoplasmic sperm injection 总被引:2,自引:2,他引:2
Intracytoplasmic sperm injection (ICSI) has increased the potential of the
assisted reproductive technologies to propagate mammalian species and has
provided an opportunity for research into cell cycle control and the
mechanisms involved in sperm-induced oocyte activation. We have
investigated the efficacy of ICSI in the rhesus monkey, the mechanism of
fertilization following sperm injection and the cytoskeletal rearrangement
that occurs upon oocyte activation. These studies were conducted on mature,
and to a lesser extent, immature oocytes. Ejaculated spermatozoa, washed,
capacitated and activated before immobilization, were injected into oocytes
using conventional ICSI methodology. Sperm injection into mature oocytes
induced oocyte activation (19/22; 86%) and pronuclear formation. In
contrast, sham- injected oocytes did not activate readily (2/16; 13%). To
localize oocyte activation factor(s), spermatozoa were separated
mechanically into heads and tails which were then injected individually
into mature oocytes. Activation occurred in 87% (20/23) of oocytes
receiving heads. After tail injection, a single microtubule aster was
nucleated and one pronucleus (PN) was seen in four of 21 oocytes.
Intracytoplasmic injection of sperm extract (SE) resulted in oocyte
activation at a significantly higher rate than occurred following sham
injection (76 versus 13%). Sperm-induced oocyte activation was also
evaluated in immature metaphase (MI) oocytes; activation occurred in 46%
(12/26) of cases; however, only 8% of the activated oocytes exhibited 2 PN.
Finally, beta-tubulin localization in untreated and taxol-treated oocytes
was established as a marker for cytoplasmic changes associated with oocyte
activation. These results are consistent with the hypothesis that
spermatozoa contain an oocyte activating factor(s) which is primarily
localized in the sperm head. Moreover, an activation response is limited to
mature oocytes and is accompanied by cytoskeletal changes analogous to
those seen following conventional fertilization.
相似文献
100.
Initiation of periovulatory events in gonadotrophin-stimulated macaques with varying doses of recombinant human chorionic gonadotrophin 总被引:2,自引:3,他引:2
Zelinski-Wooten MB; Hutchison JS; Trinchard-Lugan I; Hess DL; Wolf DP; Stouffer RL 《Human reproduction (Oxford, England)》1997,12(9):1877-1885
During in-vitro fertilization (IVF) cycles, a large bolus of human
chorionic gonadotrophin (HCG) is used to induce periovulatory events, but
the efficacy of lower doses is undefined. Following follicular stimulation
in rhesus monkeys, oocyte nuclear maturation, IVF, granulosa cell
luteinization and corpus luteum function were compared after injection of
100, 300 or 1000 IU recombinant HCG or 1000 IU urinary HCG. Bioactive HCG
rose to peak concentrations within 2 h that were proportional to the dose
administered (100 < 300 < 1000 IU, recombinant HCG = urinary HCG).
The duration of surge values (>100 ng/ml) was also dose-dependent (0 h,
100 IU; 24 h, 300 IU; >48 h, 1000 IU, recombinant and urinary HCG).
While the proportions of oocytes resuming meiosis and undergoing IVF were
similar among groups, fewer animals yielded fertilizable oocytes following
100 and 300 IU (five of nine) compared to 1000 IU recombinant and urinary
HCG (nine of 10). Peak values of serum progesterone in the luteal phase
were similar, but declined 2 days earlier after 100 and 300 IU relative to
1000 IU recombinant and urinary HCG. Thus, 3-10 fold lower doses of HCG
elicit low amplitude surges of short duration that induce periovulatory
events such as re-initiation of oocyte meiosis and granulosa cell
luteinization. However, oocyte fertilization and luteal function may
optimally require surges of higher amplitude and longer duration similar to
those produced by standard doses of 1000 IU recombinant or urinary HCG.
相似文献