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71.
Intermittent preventive sulfadoxine-pyrimethamine treatment of primigravidae reduces levels of plasma immunoglobulin G, which protects against pregnancy-associated Plasmodium falciparum malaria 下载免费PDF全文
Staalsoe T Shulman CE Dorman EK Kawuondo K Marsh K Hviid L 《Infection and immunity》2004,72(9):5027-5030
Pregnancy-associated malaria (PAM) is an important cause of maternal and neonatal suffering. It is caused by Plasmodium falciparum capable of inhabiting the placenta through expression of particular variant surface antigens (VSA) with affinity for proteoglycans such as chondroitin sulfate A. Protective immunity to PAM develops following exposure to parasites inhabiting the placenta, and primigravidae are therefore particularly susceptible to PAM. The adverse consequences of PAM in primigravidae are preventable by intermittent preventive treatment (IPTp), where women are given antimalarials at specified intervals during pregnancy, but this may interfere with acquisition of protective PAM immunity. We found that Kenyan primigravidae receiving sulfadoxine-pyrimethamine IPTp had significantly lower levels of immunoglobulin G (IgG) with specificity for the type of parasite-encoded VSA-called VSA(PAM)-that specifically mediate protection against PAM than did women receiving a placebo. VSA(PAM)-specific IgG levels depended on the number of IPTp doses received and were sufficiently low to be of clinical concern among multidose recipients. Our data suggest that IPTp should be extended to women of all parities, in line with current World Health Organization recommendations. 相似文献
72.
Plasmodium falciparum rosetting is associated with malaria severity in Kenya. 总被引:3,自引:1,他引:3 下载免费PDF全文
Rosette formation in 154 fresh Plasmodium falciparum isolates from Kenyan children with mild (n = 54), moderate (n = 64), or severe (n = 36) malaria was studied to determine whether the ability to form rosettes in vitro is correlated with malaria severity. There was a wide distribution of rosette frequencies within each clinical category; however, a clear trend towards higher rosette frequency with increasing severity of disease was seen, with the median rosette frequency of the mild-malaria group (1%; range, 0 to 82%) being significantly lower than those of the moderate-malaria group (5%; range, 0 to 45%; Mann-Whitney U test, P < 0.02) and the severe-malaria group (7%; range, 0 to 97%; Mann-Whitney U test, P < 0.003). Within the severe-malaria category there was no difference in rosetting among isolates from cerebral malaria patients or those with other forms of severe malaria. We also examined the ABO blood groups of the patients from whom isolates were obtained and found that isolates from group O patients (median rosette frequency, 2%; range 0 to 45%) rosetted less well than those from group A (median, 7%; range 0 to 82%; Mann-Whitney U test, P < 0.01) or group AB (median, 11%; range 0 to 94%; Mann-Whitney U test, P < 0.03). We therefore confirm that rosetting is associated with severe malaria and provide further evidence that rosetting is influenced by ABO blood group type. Whether rosetting itself plays a direct role in the pathogenesis of severe malaria or is a marker for some other causal factor remains unknown. 相似文献
73.
Effect of repeated high dose prophylaxis with amoxycillin on the resident oral flora of adult volunteers 总被引:1,自引:0,他引:1
Healthy adult volunteers received either single or repeated 3-g doses of amoxycillin by mouth at weekly intervals on three occasions. The salivary flora of each volunteer was monitored before, during and up to 11 weeks after the final dose of antibiotic. Viable counts of anaerobic bacteria, streptococci and streptococci resistant to amoxycillin 2 mg/L and 40 mg/L were determined in samples of saliva. All 20 volunteers harboured low numbers of streptococci resistant to amoxycillin 2 mg/L (mean count = 6.57 X 10(3) cfu/ml of saliva) before administration of the antibiotic; much lower carriage rates (45%) were observed for bacteria resistant to amoxycillin 40 mg/L (mean count = 116 cfu/ml of saliva). Each dose of amoxycillin had a rapid but transient effect on the numbers of salivary bacteria. A placebo lacking the antibiotic had no effect. A single 3-g dose of amoxycillin had little or no effect on the numbers of resistant streptococci and, therefore, it was concluded that in patients at risk of infective endocarditis a second prophylactic dose would not be invalidated. The numbers of resistant streptococci increased significantly after the second and third doses of amoxycillin, and persisted for 4-7 weeks. Consequently, in at-risk patients requiring repeated dental procedures liable to produce bacteraemia, either alternative antibiotic regimens should be used each time or intervals of at least 4 weeks should be left between treatment sessions. 相似文献
74.
Marsh DR Carson JA Stewart LN Booth FW 《Journal of muscle research and cell motility》1998,19(8):897-907
Little is known conerning promoter regulation of genes in regenerating skeletal muscles. In young rats, recovery of muscle mass and protein content is complete within 21 days. During the initial 5–10 days of regeneration, mRNA abundance for IGF-I, myogenin and MyoD have been shown to be dramatically increased. The skeletal -actin promoter contains E box and serum response element (SRE) regulatory regions which are directly or indirectly activated by myogenin (or MyoD) and IGF-I proteins, respectively. We hypothesized that the skeletal -actin promoter activity would increase during muscle regeneration, and that this induction would occur before muscle protein content returned to normal. Total protein content and the percentage content of skeletal -actin protein was diminished at 4 and 8 days and re-accumulation had largely occurred by 16 days post-bupivacaine injection. Skeletal - actin mRNA per whole muscle was decreased at day 8, and thereafter returned to control values. During regeneration at day 8, luciferase activity (a reporter of promoter activity) directed by –424 skeletal -actin and –99 skeletal -actin promoter constructs was increased by 700% and 250% respectively; however, at day 16, skeletal -actin promoter activities were similar to control values. Thus, initial activation of the skeletal - actin promoter is associated with regeneration of skeletal muscle, despite not being sustained during the later stages of regrowth. The proximal SRE of the skeletal -actin promoter was not sufficient to confer a regeneration-induced promoter activation, despite increased serum response factor protein binding to this regulatory element in electrophoretic mobility shift assays. Skeletal -actin promoter induction during regeneration is due to a combination of regulatory elements, at least including the SRE and E box. © Kluwer Academic Publishers. 相似文献
75.
Mayor NP Cox ST McWhinnie AJ Argüello JR Shaw BE Little AM Madrigal JA Marsh SG 《Tissue antigens》2005,65(1):107-109
We report here the full-length sequence of a novel HLA-A*0301 allele, A*03010103, which differs from A*03010101 by a single nucleotide substitution (G>T) at position 492 within intron 2. The variant was originally identified by Reference Strand-mediated Conformational Analysis (RSCA) and was confirmed by cloning and sequencing. The difference in RSCA mobility between A*03010101 and A*03010103 demonstrates the sensitivity of RSCA to detect single nucleotide polymorphisms. 相似文献
76.
M-type K+ currents ( I K(M) ) play a key role in regulating neuronal excitability. In sympathetic neurons, M-channels are thought to be composed of a heteromeric assembly of KCNQ2 and KCNQ3 K+ channel subunits. Here, we have tried to identify the KCNQ subunits that are involved in the generation of I K(M) in hippocampal pyramidal neurons cultured from 5- to 7-day-old rats. RT-PCR of either CA1 or CA3 regions revealed the presence of KCNQ2, KCNQ3, KCNQ4 and KCNQ5 subunits. Single-cell PCR of dissociated hippocampal pyramidal neurons gave detectable signals for only KCNQ2, KCNQ3 and KCNQ5; where tested, most also expressed mRNA for the vesicular glutamate transporter VGLUT1. Staining for KCNQ2 and KCNQ5 protein showed punctate fluorescence on both the somata and dendrites of hippocampal neurons. Staining for KCNQ3 was diffusely distributed whereas KCNQ4 was undetectable. In perforated patch recordings, linopirdine, a specific M-channel blocker, fully inhibited I K(M) with an IC50 of 3.6 ± 1.5 μM. In 70 % of these cells, TEA fully suppressed I K(M) with an IC50 of 0.7 ± 0.1 m m . In the remaining cells, TEA maximally reduced I K(M) by only 59.7 ± 5.2 % with an IC50 of 1.4 ± 0.3 m m ; residual I K(M) was abolished by linopirdine. Our data suggest that KCNQ2, KCNQ3 and KCNQ5 subunits contribute to I K(M) in these neurons and that the variations in TEA sensitivity may reflect differential expression of KCNQ2, KCNQ3 and KCNQ5 subunits. 相似文献
77.
Bolton Virginia N.; Braude Peter R.; Ockenden Kim; Marsh Simon K.; Robertson Gregory; Ross Leslie D. 《Human reproduction (Oxford, England)》1989,4(6):674-679
Twenty-nine couples with an average of 5 years of infertilitywere selected for treatment by intrauterine insemination ofwashed semen (AIH). The criteria for selection were (i) thefemale partner showed no detectable fertility disorders by routinescreening; (ii) the male partner showed subnormal semen qualityon conventional semen analysis. Ovulation was stimulated uniformlywith clomiphene citrate and precipitated with human chorionicgonadotrophin (HCG). Inseminations were performed 3132h post-HCG, with the day of HCG determined by ultrasound monitoringof follicular development. The fertilizing capacity of the malepartners spermatozoa was tested in vitro using donatedhuman oocytes and/or the zona-free hamster oocyte penetrationassay. Up to eight cycles of AIH were alternated with cyclesof natural intercourse. While no pregnancies occurred in thegroup during normal coital cycles, the AIH pregnancy rate was17% per couple, but only 3% per insemination cycle. Four furtherpregnancies were achieved spontaneously in couples from thestudy group within 3 years of completion of the AIH therapyand four patients became pregnant following subsequent GIFTor IVF treatments. Neither of the in-vitro tests was helpfulin predicting the outcome of AIH, spontaneous pregnancy norof subsequent assisted conception procedures. 相似文献
78.
Time course of hypo-osmotic swellings of human spermatozoa: evidence of ordered transition between swelling subtypes 总被引:2,自引:1,他引:2
Hossain AM; Rizk B; Barik S; Huff C; Thorneycroft IH 《Human reproduction (Oxford, England)》1998,13(6):1578-1583
The hypo-osmotic swelling test (HOST or HOS test) usually takes into
consideration the total HOS response value with no emphasis either on the
value of the response subtypes or the response evaluation time. This study
investigated the time course of HOS responses and analysed their
physiological relevance. Raw semen spermatozoa and Percoll washed
spermatozoa were used in the experiment. The morphological changes in the
sperm tail were monitored by incubating the spermatozoa in the hypo-
osmotic solution for 16 different time periods. The HOS reactive
spermatozoa and the type of HOS reaction (swelling subtypes) of the samples
subjected to different duration of treatment were identified under a phase
contrast microscope. Also the fate of individual spermatozoa in a
hypo-osmotic environment were monitored for 30 min. In spermatozoa exposed
to a hypo-osmotic solution, the motility lasted usually less than 2 min and
motility characteristics were uniquely different from that of the
spermatozoa under iso-osmotic conditions. The HOS response development was
permanent but the motility loss due to hypo-osmotic shock was reversible up
to 1 min of incubation. There was an indication of ordered transition among
the HOS swelling subtypes apparently initiating with subtype b destined to
c, d, e, f and g. Further, the subtypes a and g showed gradual decrease and
increase, respectively, while subtype b showed abrupt initial increase and
then gradual decrease. Transition from b to g could be direct or via one or
more than one subtypes. Ultrastructure based analysis indicated that HOS
response subtypes are the apparent reflection of the differences in the
cytoskeletal assembly of the sperm tail and thus may be identifying
different physiological variants in the sperm population. These results
indicate that shorter incubation is essential to document the kinetics of
various HOS responses but the conventional HOS test misses these important
HOS features because of lengthy incubation. Since the time course of
ordered transition of HOS responses will vary more than the total HOS
response in semen of different aetiologies, the importance of HOS response
subtypes and response evaluation time should be taken into consideration
when applying HOS test.
相似文献
79.
The effect of ovarian steroids on epithelial ciliary beat frequency in the human Fallopian tube 总被引:3,自引:3,他引:3
Mahmood T; Saridogan E; Smutna S; Habib AM; Djahanbakhch O 《Human reproduction (Oxford, England)》1998,13(11):2991-2994
Using a method that detects variations in light intensity we have studied
the effect of ovarian steroids on human Fallopian tube epithelial ciliary
beat frequency in vitro. We have found that baseline ciliary beat frequency
averages between 5-6 Hz. Cilia from ampullary segments of the Fallopian
tube beat significantly faster (5.4 Hz+/-0.2) than those from fimbrial
segments (4.8 Hz+/-0.2). There was no significant difference in baseline
ciliary beat frequency at any other anatomical site in the Fallopian tube.
Incubation with progesterone (10 micromol/l) suppresses human Fallopian
tube epithelial ciliary beat frequency by 40-50%. This inhibition was
observed at similar magnitudes in all Fallopian tubes studied irrespective
of anatomical site. Progesterone-induced reductions in ciliary beat
frequency were concentration dependent and prevented by the progesterone
receptor antagonist mifepristone (RU486). Oestradiol alone (10 micromol/l)
had no effect on ciliary beat frequency at any anatomical site in the
Fallopian tube but did prevent the reduction in ciliary beat frequency seen
with progesterone when tissues were incubated with these two steroids
together.
相似文献
80.
Vivek Roy Waleska S Pérez Mary Eapen Judith C W Marsh Marcelo Pasquini Ricardo Pasquini Mahmoud M Mustafa Christopher N Bredeson 《Biology of blood and marrow transplantation》2005,11(8):600-608
Patients with Diamond-Blackfan anemia (DBA) who are unresponsive to or intolerant of corticosteroids, experience treatment failure with other treatments, develop additional cytopenias or clonal disease, or opt for curative therapy are often treated with allogeneic bone marrow transplantation. We studied the transplantation outcomes of 61 DBA patients whose data were reported to the International Bone Marrow Transplant Registry between 1984 and 2000. The median age was 7 years (range, 1-32 years). Among 55 patients with available transfusion information, 35 (64%) had received > or =20 units of blood before transplantation. Most patients (67%) received their bone marrow grafts from an HLA-matched related donor. The median time to neutrophil recovery was 17 days (range, 10-119 days) and to platelet recovery was 23 days (range, 9-119 days). Five patients did not achieve neutrophil engraftment. The 100-day mortality was 18% (95% confidence interval, 10%-29%). Grade II to IV acute graft-versus-host disease occurred in 28% (range, 17%-39%) and chronic graft-versus-host disease in 26% (range, 15%-39%). The 3-year probability of overall survival was 64% (range, 50%-74%). In univariate analysis, a Karnofsky score > or =90 and transplantation from an HLA-identical sibling donor were associated with better survival. These data suggest that allogeneic bone marrow transplantation is effective for the treatment of DBA. Transplantation before deterioration of the performance status and from an HLA-identical sibling donor may improve survival. 相似文献