Resistance training for strength: effect of number of sets and contraction speed

PURPOSE: To compare effects on strength in the early phase of resistance training with one or three sets and fast or slow speeds. METHODS: A total of 115 healthy, untrained subjects were randomized to a control group or one of four training groups: one set fast (approximately 140 degrees.s(-1)), three sets fast, one set slow (approximately 50 degrees.s(-1)), or three sets slow. All subjects attended training 3 x wk(-1) for 6 wk. Subjects in the training groups performed unilateral elbow flexion contractions with a target six- to eight-repetition maximum load. Control subjects sat at the training bench but did not train. One repetition maximum strength, arm circumference, and biceps skinfold thickness were measured before and after training. RESULTS: One slow set increased strength by 25% (95% CI 13-36%, P < 0.001). Three sets of training produced greater increases in strength than one set (difference = 23% of initial strength, 95% CI 12-34%, P < 0.001) and fast training resulted in a greater increase in strength than slow training (difference = 11%, 95% CI 0.2-23%, P = 0.046). The interaction between sets and speed was negative (-15%) and of borderline significance (P = 0.052), suggesting there is a benefit of training with three sets or fast speeds, but there is not an additive benefit of training with both. CONCLUSIONS: Three sets of exercise produce twice the strength increase of one set in the early phase of resistance training. Training fast produces greater strength increases than training slow; however, there does not appear to be any additional benefit of training with both three sets and fast contractions.     

Differences in chromosome susceptibility to aneuploidy and survival to first trimester

The purpose of this study was to find specific rates of aneuploidy in cleavage-stage embryos compared with first trimester data and to evaluate post-zygotic selection against aneuploidy. A total of 2058 embryos were analysed by flurorescence in-situ hybridization (FISH), and specific aneuploidy rates were obtained for 14 chromosomes. Data from morphologically abnormal embryos could be pooled with data from preimplantation genetic diagnosis (PGD) cycles because it was observed that they had similar rates of aneuploidy; thus, for the purpose of studying aneuploidy they could be, and were, pooled. Specific chromosome aneuploidy rates were not related to morphology or development of the embryos. The average maternal age of patients with aneuploid embryos was significantly higher than the overall analysed population. Monosomy appeared more commonly than trisomy. The chromosomes most frequently involved in aneuploidy were (in order) 22, 16, 21 and 15. When compared with first trimester pregnancy data, aneuploidies detected at cleavage stage seem to die in excess of 90% before reaching first trimester, with the exception of chromosome 16 and gonosomes (76% and 14% respectively). Differences in chromosome-specific aneuploidy rates at first trimester conceptions are probably produced by different chromosome-specific aneuploidy rates at cleavage stage and different survival rates to first trimester.     

Predictability of preimplantation genetic diagnosis of aneuploidy and translocations on prospective attempts

The aim of this study was to determine if the outcomes of aneuploidy and translocation testing by preimplantation genetic diagnosis (PGD) at the 8-cell stage have a predictive value for new genetic diagnosis cycles. In total, 83 cycles (39 patients) undergoing PGD of translocations and 378 cycles (176 patients) of aneuploidy were included. Predictability, defined as having similar rate (+/-20%) of euploid embryos in the first and successive cycles, was found in 66% of patients undergoing aneuploidy testing. Predictability was found significantly more often in patients undergoing PGD of translocations (90%, P = 0.006). In addition, patients with 0, <30 or > or =30% euploid embryos in the first cycle were compared and groups 0 and <30% had significantly fewer euploid embryos in the second cycle (22-26%) than those of the group with > or =30% (37%) (P < 0.05). Patients who did not become pregnant after the first attempt were stimulated more aggressively than those becoming pregnant, producing significantly more embryos in the second than in the first cycle (P < 0.001). Therefore, correlation between euploidy rate and pregnancy rate could not be assessed objectively between cycles. In conclusion, the PGD results of a first cycle can predict the results of the second cycle, but this is likely to be of more value when the condition investigated is translocation rather than aneuploidy. The chance of pregnancy is usually related to the number of euploid embryos.     

Indoleamine 2,3-dioxygenase expression is restricted to fetal trophoblast giant cells during murine gestation and is maternal genome specific

Pharmacologic inhibition of indoleamine 2,3 dioxygenase (IDO) activity during murine pregnancy results in rejection of allogeneic fetuses by the maternal immune system. Here, we show that IDO expression is restricted to perinuclear regions of primary trophoblast giant cells (TGCs) of fetal origin at mid-gestation (E10.5). After placentation (E14), no IDO expression was detected at the maternal-fetal interface. Matings involving IDO-deficient females revealed that paternally inherited IDO alleles were inactive in primary TGCs, presumably due to paternal genome-specific gene inactivation. Allogeneic matings in which both parents were genetically IDO-deficient produced litters of normal sizes at normal rates compared to IDO-sufficient parental mice, implying that compensatory or redundant immunosuppressive mechanisms protected allogeneic fetuses during gestation in IDO-deficient mice. Consistent with this notion, treatment with IDO inhibitor did not affect allogeneic pregnancy rates when both parents were IDO-deficient, confirming that IDO was the relevant pharmacologic target of the IDO inhibitor in matings involving IDO-sufficient mice. Hence, IDO is a key immunosuppressive mechanism in normal murine pregnancies, and it is regulated entirely through maternally inherited fetal genes.     

Increased rate of aneuploid embryos in young women with previous aneuploid conceptions

OBJECTIVES: To determine whether a history of a previous aneuploid conception increases the rate of aneuploidy among women having preimplantation diagnosis (PGD). METHODS: Preimplantation embryos were tested for aneuploidy using FISH probes specific for chromosomes 13,15,16,17,18,21,22,X and Y.Using logistic regression to control for maternal age, we compared the rates of aneuploidy and other chromosome errors in 344 embryos from women having PGD because of a history of a previous aneuploid conception, 363 embryos from 42 women having PGD because of X-linked disorders and 1158 embryos from 135 women having PGD because of repeated in vitro fertilization failure. RESULTS: The frequency of aneuploidy differed significantly among patient groups for women younger than 35 (p = 0.003) but not for women older than 35. In women < 35, the rate of detected aneuploidy was 37.4% in the Aneuploid group, 20.9% in the X-linked group and 27.0% in the RIF group. (p = 0.0003 when the control groups are combined). The frequency of other chromosome abnormalities, as well as pregnancy and implantation rates, did not differ significantly among patient groups. CONCLUSIONS: This study suggests that a history of a trisomic pregnancy, whether or not it was a viable trisomy, is associated with an increased risk of another aneuploid conception at conception.     

The way to a man's heart is through his stomach: much 'diaphragmatic' attenuation is likely gastric, and effervescent granules enhance cardiac imaging

Avoidance of falsely positive results depends on distinguishing reality from artifact, in turn depending on images of highest quality. In radionuclide cardiac imaging, an inferior wall artifactual defect, so called "diaphragmatic attenuation", is particularly common and vexing. Despite the historically held view, analysis and review of the literature suggest the defect is likely not diaphragmatic but rather primarily due to attenuation by nearby stomach wall. The explanation is based on gravity and anatomy. With this improved understanding, effervescent granules were given as a clinical, nonresearch measure to nine patients during myocardial scanning. It was observed that two-thirds demonstrated moderate or marked lessening of attenuation. An additional benefit is lessening of artifact by extracardiac activity. These benefits may also apply to other sorts of cardiac radionuclide imaging. The significance of this new imaging method is discussed and various avenues of research are proposed.     

Differential gene expression in metastasizing cells shed from kidney tumors

We developed a novel orthotopic mouse tumor model of renal cell carcinoma to collect and characterize cells spontaneously shed from SN12C (renal cell carcinoma) and SN12L1 (high metastatic variant of SN12C) tumors grown in kidneys of severe combined immunodeficient mice. Viability of the shed cell population was greater for SN12L1 tumors (25%) compared with SN12C tumors (11%, P < 0.05). Gene array analysis of 23 genes involved in metastasis showed that CD44, alpha3 integrin, and caveolin were down-regulated in the shed tumor cells compared with their primary counterparts, and blocking alpha3 integrin or CD44 function inhibited attachment and migration of both cell lines. These results suggest that cohesion of the cells within the primary tumor mediated by CD44 and alpha3 integrins hinders metastasis and that shedding is a passive process not necessarily mediated by cell migration in these tumors. Furthermore, resistance to apoptosis may enhance metastasis in the higher metastatic tumor.     

The separateness of social and emotional loneliness in childhood

BACKGROUND: Much of the childhood loneliness research is misleading because it confounds objective and subjective measures of loneliness. The overall aim of this research was to examine the relationship between social isolation and emotional loneliness. METHOD: Three extreme groups were identified in a sample of 640 4-9-year-old children. There were two ('rejected' [N=60] and 'lonely' [N=146]) in which social and emotional loneliness were unrelated. The first were socially isolated (rejected) but they did not feel lonely. The second group felt lonely but they were not socially isolated. The third group ('rejected/ lonely') consisted of 61 children who were rejected and also felt lonely. RESULTS: Felt loneliness and social rejection were experienced together by 61 children, but 206 children experienced either one or the other, but not both. The fourth and largest group [N=374] were neither rejected nor lonely. Differences between the groups were found on direct observation measures of solitariness, sociability, and aggression; peer reports of shyness, aggression, prosocial behaviour, disruptive behaviour and inability to take teasing; self-reports of self-worth and competence, self-reports of supportive relationships; and measures of language use. CONCLUSIONS: The results indicate that it is loneliness and not rejection that co-occurs with emotional problems.     

Macrophages and the regulation of self-reactive T cells

Macrophages are professional scavengers of apoptotic and necrotic cells, and hence constantly take up self antigens. Paradoxically, macrophages are also professional antigen-presenting cells, which would seem to invite autoimmune disorders. Moreover, macrophages are effector cells in the tissue-destruction phase of autoimmune disorders, where they encounter additional self antigens in the stimulatory context of chronic inflammation. This review examines the array of immunosuppressive mechanisms which may help macrophages suppress unwanted T cell responses, and considers the consequences of a breakdown in these negative-regulatory systems in autoimmunity.