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11.
The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity 总被引:20,自引:6,他引:20
Hughes CM; Lewis SE; McKelvey-Martin VJ; Thompson W 《Human reproduction (Oxford, England)》1998,13(5):1240-1247
The integrity of sperm DNA is crucial for the maintenance of genetic
health. A major source of damage is reactive oxygen species (ROS)
generation; therefore, antioxidants may afford protection to sperm DNA. The
objectives of the study were, first, to measure the effects of antioxidant
supplementation in vitro on endogenous DNA damage in spermatozoa using the
single cell gel electrophoresis (comet) assay and, second, to assess the
effect of antioxidant supplementation given prior to X-ray irradiation on
induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll
centrifugation in the presence of ascorbic acid (300, 600 microM), alpha
tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5,
10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand
breakage was measured using the comet assay. Sperm DNA was protected from
DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60
microM) and urate (400 microM). These antioxidants provided protection from
subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or
ascorbate and alpha tocopherol together induced further DNA damage.
Supplementation in vitro with the antioxidants ascorbate, urate and alpha
tocopherol separately has beneficial effects for sperm DNA integrity.
相似文献
12.
Kirkpatrick SE; Pitlick PT; Naliboff J; Friedman WF 《The American journal of physiology》1976,231(2):495-500
13.
Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization 总被引:11,自引:0,他引:11
The development and application of fluorescence in-situ hybridization
(FISH) has opened the way for comprehensive studies on numerical chromosome
abnormalities in human spermatozoa. FISH can be rapidly applied to large
numbers of spermatozoa and thus overcomes the major limitation of
karyotyping spermatozoa after penetration of zona-free hamster oocytes. The
simultaneous hybridization of two or more chromosome-specific probes to
spermatozoa and subsequent detection of the bound probes using different
fluorescent detection systems enables two or more chromosomes to be
localized simultaneously in the same spermatozoon and provides a technique
for undertaking reasonable estimates of aneuploidy. The most commonly used
probes are those which bind to the centromeric region of specific
chromosomes. Most studies to date have concentrated on estimating
aneuploidy in spermatozoa from normospermic men, although reports are
beginning to appear on aneuploidy in spermatozoa from subfertile and
infertile men. Multi- probe FISH studies have generally reported disomy
(hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary
evidence that some chromosomes such as X, Y and 21 are predisposed towards
higher rates of non-disjunction during spermatogenesis. There are also
suggestions of inter-donor variability in aneuploidy frequencies for
specific chromosomes, although this requires confirmation in larger
studies. While FISH is clearly a powerful technique that has many
applications in reproductive medicine, it must also be realized that it
does have limitations and the technology itself is still evolving and has
yet to be fully validated on spermatozoa.
相似文献
14.
SE Andrew 《Clinical genetics》2003,64(4):293-296
15.
Time-on-task decrements in "steer clear" performance of patients with sleep apnea and narcolepsy. 总被引:8,自引:2,他引:8
Loss of attention with time-on-task reflects the increasing instability of the waking state during performance in experimentally induced sleepiness. To determine whether patients with disorders of excessive sleepiness also displayed time-on-task decrements indicative of wake state instability, visual sustained attention performance on "Steer Clear," a computerized simple RT driving simulation task, was compared among 31 patients with untreated sleep apnea, 16 patients with narcolepsy, and 14 healthy control subjects. Vigilance decrement functions were generated by analyzing the number of collisions in each of six four-minute periods of Steer Clear task performance in a mixed-model analysis of variance and linear regression equations. As expected, patients had more Steer Clear collisions than control subjects (p=0.006). However, the inter-subject variability in errors among the narcoleptic patients was four-fold that of the apnea patients, and 100-fold that of the controls volunteers; the variance in errors among untreated apnea patients was 27-times that of controls. The results of transformed collision data revealed main effects for group (p=0.006), time-on-task (p=0.001), and a significant interaction (p=0.022). Control subjects showed no clear evidence of increasing collision errors with time-on-task (adjusted R2=0.22), while apnea patients showed a trend toward vigilance decrement (adjusted R2=0.42, p=0.097), and narcolepsy patients evidenced a robust linear vigilance decrement (adjusted R2=0.87, p=0.004). The association of disorders of excessive somnolence with escalating time-on-task decrements makes it imperative that when assessment of neurobehavioral performance is conducted in patients, it involves task durations and analyses that will evaluate the underlying vulnerability of potentially sleepy patients to decrements over time in tasks that require sustained attention and timely responses, both of which are key components in safe driving performance. 相似文献
16.
17.
Debelenko LV; Brambilla E; Agarwal SK; Swalwell JI; Kester MB; Lubensky IA; Zhuang Z; Guru SC; Manickam P; Olufemi SE; Chandrasekharappa SC; Crabtree JS; Kim YS; Heppner C; Burns AL; Spiegel AM; Marx SJ; Liotta LA; Collins FS; Travis WD; Emmert-Buck MR 《Human molecular genetics》1997,6(13):2285-2290
Lung carcinoids occur sporadically and rarely in association with multiple
endocrine neoplasia type 1 (MEN1). There are no well defined genetic
abnormalities known to occur in these tumors. We studied 11 sporadic lung
carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene
on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy
fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was
studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene
were inactivated. All four tumors showed the presence of a MEN1 gene
mutation and loss of the other allele. Observed mutations included a 1 bp
insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide
substitution affecting a donor splice site. Each mutation predicts
truncation or potentially complete loss of menin. The remaining seven
tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH.
The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a
complex germline MEN1 gene mutation. The data implicate the MEN1 gene in
the pathogenesis of sporadic lung carcinoids, representing the first
defined genetic alteration in these tumors.
相似文献
18.
Frequency/amplitude characteristics of postural tremor of the hands in a population of patients with bilateral essential tremor: implications for the classification and mechanism of essential tremor. 总被引:1,自引:0,他引:1 下载免费PDF全文
S Calzetti M Baratti M Gresty L Findley 《Journal of neurology, neurosurgery, and psychiatry》1987,50(5):561-567
Amplitude/frequency characteristics of postural hand tremor in 59 patients with bilateral essential tremor of various degrees of severity were assessed using accelerometric recordings and spectral analysis. Intra-subject comparisons of tremor characteristics between the more and less affected hands were used to control for variability of tremor due to age factors and intersubject differences in amplitude and frequency. Statistical analysis distinguished three different patient groups. Some patients had low amplitude (less than 0.1-0.015 cm) tremor in the less affected limb (which tended to be 7 Hz or more in frequency in the young) and a larger amplitude tremor in the more affected hand which was 1 Hz or more lower in frequency. Other subjects had either bilaterally small or bilaterally large amplitude tremors of similar frequencies. These findings imply that there is a downwards step in frequency between symptomatic tremors of small and large amplitude. The amplitude and frequency of the small amplitude tremors were unrelated but frequency declined with age. The frequency of the large amplitude tremor was generally determined by amplitude but a wide range of amplitudes were compatible with similar frequencies. The frequency of large amplitude tremor also declined with age. It was concluded that there are two types of essential tremor, the smaller amplitude tremor probably derives from an exaggeration of some or all of the mechanisms of normal physiological tremor whereas the larger amplitude tremor probably arises from a separate "pathological" central nervous mechanism. It is not known if or how one may transform into, or be replaced by, the other during progression of the disease. 相似文献
19.
P G Bain L J Findley P Atchison M Behari M Vidailhet M Gresty J C Rothwell P D Thompson C D Marsden 《Journal of neurology, neurosurgery, and psychiatry》1993,56(8):868-873
A clinical rating scale which measured the severity of tremor in 20 patients (12 with essential tremor and 8 with "dystonic" tremor) was assessed at specific anatomical sites for both inter and intra-rater reliability using four raters. The scores obtained with the scale were compared with the results of upper limb accelerometry, an activity of daily living self-questionnaire and estimates of the tremor induced impairment in writing and drawing specimens. The results show that, for the purposes of routine assessment and therapeutic trials, a clinical rating scale can produce reliable results which are a more valid index of tremor induced disability than standard postural accelerometry. 相似文献
20.
Findley ME 《Health facilities management》1991,4(2):24, 26, 28