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排序方式: 共有4115条查询结果,搜索用时 140 毫秒
1.
Twin study of genetic and environmental effects on lipid levels 总被引:4,自引:0,他引:4
D L O'Connell R F Heller D C Roberts J R Allen J C Knapp P L Steele D Silove 《Genetic epidemiology》1988,5(5):323-341
A study of 106 pairs of monozygotic (MZ) and 94 pairs of dizygotic (DZ) twins tested the hypothesis that part of the previously described genetic influence on blood lipid levels can be ascribed to closer similarities among MZ than among DZ twin pairs in environmental factors that affect lipid levels. Participants were adult twin volunteers (age 17-66; 64 male and 136 female pairs) who were selected from the NH & MRC Twin Registry or were respondents to advertisements. They completed a 4-day weighed food diary from which mean nutrient intake was derived. Information on lifestyle and demographic variables was obtained by questionnaire and a nonfasting blood sample was taken for measures of total, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol and the HDL2 and HDL3 subfractions. Height and weight were measured, and body mass index (BMI) was calculated (kg/m2). Estimates of the heritability of sex-adjusted lipid levels were 0.72 for total cholesterol, 0.79 for HDL cholesterol, 0.69 for HDL2, 0.20 for HDL3, 1.06 for LDL cholesterol, and 0.44 for sex-adjusted BMI. In all cases except for HDL3, genetic variance was statistically significant. After adjusting for the effects of environmental variables in three different ways, the estimates of heritability were somewhat lower for total cholesterol, HDL2, and BMI, and those for HDL cholesterol (borderline) and LDL cholesterol (definitely) remained statistically significant but were decreased. A genetic influence on HDL3 was not found. Adjusted heritability estimates obtained from one method of analysis were 0.35 for total cholesterol, 0.49 for HDL, 0.04 for HDL2, -0.34 for HDL3, 0.66 for LDL, and 0.32 for BMI. These results suggest that the assumptions made in the classical twin study approach are not appropriate when examining genetic effects on lipid levels or BMI, or indeed on any biological variable that may be affected by environmental factors that tend to be more similar in MZ twins than in DZ twins. In these circumstances, more complex models may be needed to differentiate between genetic and environmental influences. 相似文献
2.
Correction of distal femoral deformity 总被引:1,自引:0,他引:1
This retrospective study reviews 12 distal femoral osteotomies in nine patients performed for angular and rotational deformities, using the Orthofix external fixator. All osteotomies progressed to solid union with reliable correction of the deformity. Few complications were encountered. Simultaneous lengthening was performed on one patient successfully. This method proved to be a safe and precise means of correcting distal femoral deformity with the option of simultaneous correction of length discrepancy. 相似文献
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INVOLVEMENT OF NON-NMDA AND NMDA RECEPTORS IN GLUTAMATE-INDUCED PRESSOR OR DEPRESSOR RESPONSES OF THE PONS AND MEDULLA 总被引:1,自引:0,他引:1
SY Chen WC Wu CJ Tseng JS Kuo CY Chai 《Clinical and experimental pharmacology & physiology》1997,24(1):46-56
1. Fifty-five intact and six baroreceptor denervated and vagotomized cats of either sex were anaesthetized intraperito-neally with urethane (400 mg/kg) and a-chloralose (40 mg/kg). Responses of the systemic arterial pressure (SAP), mean SAP (MSAP) and sympathetic vertebral nerve (VNA) and renal nerve activities (RNA) were recorded. 2. In intact animals, monosodium L-glutamate (Glu, 0.1 mol/L, 50 nL) was microinjected into pressor areas of the locus coeruleus (LC), gigantocellular tegmental field (GTF), rostral ventrolateral medulla (RVLM) and dorsomedial medulla (DM), and the depressor areas of caudal ventrolateral medulla (CVLM). The induced actions were compared before and after microinjection of either glutamate antagonists, glutamate diethylester (GDEE, 0.5 mol/L, 50–100nL), a competitive AMPA receptor blocker, or 2-amino-5-phosphonovaleric acid (D-AP5, 0.025 mol/L, 50–100 nL), a competitive N-methyl-D-aspartate (NMDA) receptor blocker. GDEE completely blocked the increases of SAP and VNA elicited from all pressor areas. D-AP5 only partially blocked the pressor but slightly blocked VNA and RNA responses from LC, GTF and DM, particularly those from RVLM. Neither GDEE nor D-AP5 blocked the depressor responses of SAP and two nerve activities elicited from CVLM. 3. In baroreceptor denervated animals, NMDA (2 mmol/L, 50–100 nL) and AMPA (0.2 mmol/L, 50–100 nL) were micro-injected into the same pressor areas of GTF, RVLM and DM and the depressor area of CVLM responsive to Glu activation (0.1 mol/L, 30 nL). In RVLM, DM and CVLM, the results of either NMDA or AMPA were similar to those induced by Glu. However, in GTF, microinjection of either NMDA or AMPA did not induce similar responses to Glu. This suggests that the nature of GTF may differ from RVLM and DM. 4. The above results suggest that the Glu-induced pressor responses from LC, GTF, DM and especially RVLM, are primarily mediated through AMPA receptors. The Glu-induced depressor responses from CVLM may not be predominantly mediated by either AMPA or NMDA receptors. 5. In both baroreceptor-intact and -denervated cats stimulation of the pressor areas often produced an increase of VNA and a decrease of RNA, while in the depressor CVLM decreased both VNA and RNA. The VNA, but not RNA were positively correlated with the pressor responses, while both VNA and RNA were positively correlated with the depressor responses. This may suggest that neurons of the sympathetic vertebral and renal nerves are topographically organized in the brain. 相似文献
5.
Hillmann JS; Mesgarzadeh M; Revesz G; Bonakdarpour A; Clancy M; Betz RR 《Radiology》1987,165(3):769-773
Proximal femoral focal deficiency, an uncommon congenital anomaly, necessitates early radiologic classification for surgical planning and treatment. Objective radiographic criteria, including femoral length index, acetabular depth index, acetabular angle index, and shape of the proximal femur were determined in 49 patients before cartilaginous ossification of the femoral capital epiphysis; final classification was based on follow-up radiographs or findings at arthrography or surgery. These parameters were analyzed to determine the accuracy and contributions of each in classification. Correct classification into one of three groups was possible in 86% of cases with use of three of the parameters: femoral length index, acetabular depth index, and shape of the proximal femur. The acetabular angle was found to contribute insignificantly to classification. Magnetic resonance imaging, used in only one case, depicted the nonossified cartilaginous femoral capital epiphysis, thus obviating the need for invasive diagnostic procedures and facilitating early classification. 相似文献
6.
Antibody-antigen complex formation following injection of OC125 monoclonal antibody in patients with ovarian cancer 总被引:3,自引:0,他引:3
H J Haisma A Battaile E W Stradtman R C Knapp V R Zurawski 《International journal of cancer. Journal international du cancer》1987,40(6):758-762
Monoclonal antibody (MAb) OC125 binds to approximately 80% of epithelial ovarian cancers. Serum antigen, CA125, can be detected in these patients. 131I-OC125-F(ab')2 was injected into 5 ovarian carcinoma patients with preinjection serum levels of 150 to 9,000 CA125 U/ml. Patients received the antibody intravenously in doses ranging from 0.46 to 0.94 mg with a specific activity of approximately 2.5 mCi/mg 131I. The half-life in the circulation was approximately 30 hr and was independent of serum CA125 levels. Clearance of 131I from the circulation fitted an open, one-compartment mathematical model. Gel filtration chromatography revealed antibody-antigen complexes in sera 15 min after injection of the radiolabelled antibody. By 5 days after injection, the free form of OC125 antibody could not be detected in the serum. The rate of complex formation correlated well with the observed preinjection serum CA125 levels. This direct correlation was verified in vitro using purified CA125 antigen and radiolabelled OC125 F(ab')2 fragments. The specific effects of complex formation on tumor localization remains unclear. However, the presence of complexes should not be ignored, when planning for diagnostic imaging or immunotherapy with OC125 or other MAbs reacting with circulating antigen. 相似文献
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Véronique Strijckmans Michel Bottlaender Humin Luo Michèle Ottavianil Daniel W. McPherson Christian Loc'h Chantal Fuseau Furn F. Knapp Bernard Mazière 《European journal of nuclear medicine and molecular imaging》1997,24(5):475-482
We studied the potential of three radiobrominated isomers of BrQNP, (Z(-,-)-[76Br]BrQNP,E(-,-)-[76Br]BrQNP andE(-,+)-[76Br]BrQNP), as suitable radioligands for imaging of central muscarinic cholinergic receptors in the human brain. These radioligands were stereospecifically prepared by electrophilic radiobromodestannylation of the respective tributylstannyl precursors using no-carrier-added [76Br]BrNH4 and peracetic acid. Preliminary pharmacological characterizations were determined by biodistribution, autoradiography, competition, displacement and metabolite studies in rats. The (-,-)-configuration presented important specific uptakes in brain muscarinic cholinergic receptor (mAChR)-rich structures and in heart, low metabolization rates and an apparent M2 selectivity. The (-,+)-configuration revealed more rapid clearance, lower uptake, a higher metabolization rate and an apparent M1 selectivity. Reversibility of the binding was confirmed for the three radiotracers. Positron emission tomography in the living baboon brain revealed high and rapid uptake in the brain and accumulation in the mAChR-rich structures studied. At 30 min p.i., theE(-,-)-radiotracer reached a plateau in cortex, pons and thalamus with concentrations of 29%, 24% and 19% ID/l, respectively.Z(-,-)-[76Br]BrQNP also accumulated in these structures, reaching a maximal uptake (27% ID/l) in the cortex 2 h p.i. At 5 min p.i. a plateau (17% ID/l) was only observed in the cortex for theE(-,+)-[76Br]BrQNP; by contrast, the other structures showed slow washout. After 3 weeks, the (-,-)-radiotracers were studied in the same baboon pretreated with dexetimide (1 mg/kg), a well-known muscarinic antagonist. In all the mAChR structures, the highly reduced uptake observed after this preloading step indicates that these radiotracers specifically bind to muscarinic receptors.Z(-,-)-[76Br]BrQNP, which is displaced in higher amounts from M2 mAChR-enriched structures, reveals an M2 affinity. The two isomers having the (-,-)-configuration are potential probes for investigating central muscarinic receptors. The absolute configuration on the acetate chiral centre influences their muscarinic subtype selectivity and thecis-trans isomerism of the vinyl moiety affects their specific fixation. 相似文献
9.
Henryk Barthel Michael Wiener Claudia Dannenberg Simone Bettin Bernhard Sattler Wolfram H. Knapp 《European journal of nuclear medicine and molecular imaging》1997,24(10):1245-1252
This study addresses the question of whether the normal range for distribution of local cerebral blood flow (lCBF) in adults
can be transferred to the 4- to 15-year-old age group. Twenty-three children (age: 4–15 years; mean 11±3 years, group I) and
10 adults (age: 27–56 years; mean 45±10 years, group II) without evidence of cerebrovascular disease or other brain diseases
underwent technetium-99m ethyl cysteinate dimer single-photon emission tomography. Counts in cortical and subcortical regions
of interest (ROIs) were related to those in cerebellar ROIs (= 100%). Relative cortical activity in group I exceeded that
in group II, particularly in left parietal (107.6%±9.8% vs 84.1%±12.4%), left frontal (97.7%±6.7% vs 79.4%±8.9%) and left
temporal areas (99.7%±7.4% vs 84.9%±10.1%) and in the cingulate cortex (112.1%±9.1% vs 95.9%±10.1%, P<0.05). Cerebral activity uptake per injected dose was inversely correlated with age in 19 children of group I (r = –0.77, P<0.001). In group I, there was also an inverse correlation between age and the relative local count density in the parietal
(r = –0.42 to –0.57), frontal (r = –0.48), temporal (r = –0.42 to –0.58) and occipital cortex (r = –0.44). In these cortical regions relative counts differed when subgroups of children aged 4–10 and 11–15 years were analysed.
It is concluded that there are systematic differences between 4- to 15-year-old children and adults with regard to normal
lCBF. Diagnostic use of perfusion agents has to consider age-adjusted normal flow maps; normal ranges should be determined
separately for the age groups 4–10 and 11–15 years.
Received 23 March and in revised form 11 July 1997 相似文献
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