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21.
Well-organised cervical screening programmes have reduced the mortality from cervical cancer by up to 50% in the developed world. Despite the successful development of human papilloma virus vaccines, there is likely to remain a need for cervical screening for the foreseeable future. In contrast, the value of mass screening for ovarian cancer remains unproven, although current screening methods can detect early-stage disease in asymptomatic individuals. Breast screening does appear to be associated with a reduction in mortality in the long term but paradoxically may increase death rates in young women in the short term. Testing for sexually transmitted infections is effective in reducing morbidity but tends to be selective at present because of concerns over the cost and psychosocial implications of general population screening.  相似文献   
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Background  

Some studies have found that lower parity and higher or lower social class (depending on the study) are associated with increased risks of childhood acute lymphoblastic leukaemia (ALL). Such findings have led to suggestions that infection could play a role in the causation of this disease. An earlier New Zealand study found a protective effect of parental marriage on the risk of childhood ALL, and studies elsewhere have reported increased risks in relation to older parental ages. This study aimed to assess whether lower parity, lower social class, unmarried status and older parental ages increase the risk of childhood ALL (primarily). These variables were also assessed in relation to the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin's lymphomas and Hodgkin's disease.  相似文献   
25.
After bone marrow transplantation (BMT), a prolonged dysregulation of humoral immunity can be observed. In the present study, we investigated whether this is reflected in an abnormal production of specific antibodies (Ab) to the T-cell-dependent recall antigen tetanus-toxoid (TT). The study group consisted of children receiving transplants of an unmodified allogeneic graft and of adults receiving either a T-cell- depleted allogeneic or an unmodified autologous BM graft. Findings were compared with those in healthy controls. In pediatric graft recipients, who were routinely revaccinated early after BMT, the Ab response was quantitatively superior to that in adult graft recipients who did not receive early revaccination. In the majority of graft recipients, the time period after vaccination required to reach the peak level of antibodies was prolonged and the number of responding TT-specific B- cell clones was markedly decreased in comparison with controls. In controls, a low frequency of dominant B-cell clones may produce low quantities of homogeneous Ab components (H-Ab) against a heterogeneous background. However, in BM graft recipients, "overshooting" of Ab production by separate B-cell clones was observed, resulting in the development of H-Ab at a relatively high concentration. These abnormalities were present up to 10 years after BMT, irrespective of either the age of the recipient, the modulation of the graft, or the vaccination schedule used. It is hypothesized that the dysregulated Ab production is the consequence of activation of a restricted number of resting memory B cells, present in germinal centers, repopulating gradually after BMT. Our data show that routine revaccination early after BMT improves the humoral immune response. However, because of a clonally dysregulated Ab production, long-lasting qualitative defects may be present even after normalization of Ab titers.  相似文献   
26.
An adverse environment around conception and implantation influences later fetal growth and development to term in humans and sheep. Indeed, preimplantation undernutrition of rats elevated the systolic blood pressure of the resultant adult offspring. In this study, adult cardiovascular function is examined in a slower growing, non-litter-bearing species after peri-implantation undernutrition. Eight ewes were fed to 50% equivalent food intake of 12 control ewes from 1 to 30 days (term approximately 147 days) only. Following consumption of an adequate diet to term, natural lambing, and then weaning, resting cardiovascular status and baroreflex function were examined in the resultant young adult offspring. Birth weight and postnatal growth to 1 year of age were unaffected by early undernutrition; however, nutrient-restricted sheep had increased pulse pressure, a reduced rate pressure product, and a leftward shift in their baroreflex function curve. Baroreflex sensitivity during angiotensin II infusion was also blunted in early nutrient-restricted sheep but the tachycardia following a reduction in central blood pressure appeared potentiated, relative to controls. The data suggest that peri-implantation undernutrition may program long-term cardiovascular dysfunction that ultimately increases the risk of hypertension later in life. An increase in regional angiotensin II activity during this critical early phase of development is a likely candidate mechanism for the effects observed. The data have broad implications for the health outcome of those offspring from mothers who were poorly nourished during early, often unknown pregnancy and for embryos artificially manipulated because of infertility treatment.  相似文献   
27.
Summary. We have previously derived a cell strain which had both mast cell and monocytic properties from the bone marrow of a child with diffuse cutaneous mastocytosis. This cell strain, termed HBM-M, consisted of two cell populations both of which possessed certain ultrastructural, cytochemi-cal and surface phenotypic features of degranulated mast cells. The cells also displayed cytochemical and surface phenotypic features of monocytes. These cells may represent a common bone marrow derived mast cell/monocyte precursor. Studies of human mast cells have been hindered by the fact that it is difficult to establish such cells in long-term culture. Thus, we sought to immortalize HBM-M cells by introducing Simian virus 40 large T-antigen. Following transfection by the strontium phosphate technique, transformed cells were selected, expanded and passaged until the cells entered a non-proliferative phase termed crisis. Certain clones passed through crisis 3 months later and by this means two immortal cell lines, HBM-MI-1 and HBM-MI-2, were obtained. The criterion for immortality was growth for greater than 100 population doublings. The immortal cell lines retained some, but not all. of the mast cell and monocytic properties of the original HBM-M cell strain. The immortalization of the cell strain HBM-M provides an opportunity to investigate the mast cell and monocytic properties of these cells, and the apparent relationship between mast cells and monocytes.  相似文献   
28.
Genotype 2 hepatitis C virus (HCV) accounts for up to 30% of chronic HCV infections in Japan. The standard of care for patients with genotype 2 HCV – peginterferon and ribavirin for 24 weeks – is poorly tolerated, especially among older patients and those with advanced liver disease. We conducted a phase 3, open‐label study to assess the efficacy and safety of an all‐oral combination of the NS5B polymerase inhibitor sofosbuvir and ribavirin in patients with chronic genotype 2 HCV infection in Japan. We enrolled 90 treatment‐naïve and 63 previously treated patients at 20 sites in Japan. All patients received sofosbuvir 400 mg plus ribavirin (weight‐based dosing) for 12 weeks. The primary endpoint was sustained virologic response at 12 weeks after therapy (SVR12). Of the 153 patients enrolled and treated, 60% had HCV genotype 2a, 11% had cirrhosis, and 22% were over the aged 65 or older. Overall, 148 patients (97%) achieved SVR12. Of the 90 treatment‐naïve patients, 88 (98%) achieved SVR12, and of the 63 previously treated patients, 60 (95%) achieved SVR12. The rate of SVR12 was 94% in patients with cirrhosis and in those aged 65 and older. No patients discontinued study treatment due to adverse events. The most common adverse events were nasopharyngitis, anaemia and headache. Twelve weeks of sofosbuvir and ribavirin resulted in high rates of SVR12 in treatment‐naïve and previously treated patients with chronic genotype 2 HCV infection. The treatment was safe and well tolerated by patients, including the elderly and those with cirrhosis.  相似文献   
29.
Mouse model systems which allow bone marrow reconstitution can be used to analyse genetically programmed leukemia. The original and most widely used system is that of post 5-fluorouracil mouse hematopoietic stem cells (HSC) into lethally irradiated syngeneic mice. Another more recent system allows analysis of human HSCs in the NOD-SCID mouse. Both systems are discussed as models for analysis of gene induced leukemia.  相似文献   
30.
The present study aimed to determine whether porcine genotype and/or postnatal age influenced mRNA abundance or protein expression of uncoupling protein (UCP)2 or 3 in subcutaneous adipose tissue (AT) and skeletal muscle (SM) and the extent to which these differences are associated with breed-specific discordance in endocrine and metabolic profiles. Piglets from commercial and Meishan litters were ranked according to birth weight. Tissue samples were obtained from the three median piglets from each litter on either day 0, 4, 7, 14 or 21 of neonatal life. UCP2 protein abundance in AT was similar between genotypes on the first day of life, but it was elevated at all subsequent postnatal ages (P<0.05) in AT of Meishan piglets. In contrast, UCP2 mRNA abundance was lower in Meishans up to 14 days of age. UCP2 mRNA expression was not correlated with protein abundance in either breed at any age. UCP3 mRNA in AT was similar between breeds up to day 7; thereafter, expression was higher (general linear model, P<0.05) in Meishan piglets. Conversely, UCP3 mRNA expression in SM was higher in commercial piglets after day 7. Colonic temperature remained lower in Meishan than commercial piglets throughout the study; this was most obvious in the immediate post-partum period when Meishan piglets had lower (P<0.05) plasma triiodothyronine. In conclusion, we have demonstrated that porcine genotype influences the expression and abundance of UCP2 and 3, an influence which may, in part, be due to the distinctive endocrine profiles associated with each genotype.  相似文献   
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