Chromatin structure during the prereplicative phases in the life cycle of mammalian cells

The object of this study was to determine the kinetics of chromosome decondensation during the G₁ period of the HeLa cell cycle. HeLa cells synchronized in the G₁ period following the reversal of mitotic block were fused with Colcemid-arrested mitotic HeLa cells at 1.5, 3, 5, and 7 h after the reversal of N₂O block. The resulting prematurely condensed chromosomes (PCC) were classified into six categories depending on the degree of their condensation. The frequency of occurrence of each category was plotted as a function of time after mitosis. The results of this study indicate that the process of chromosome decondensation, initiated during the telophase of mitosis continues throughout the G₁ period without any interruption, thus the chromatin reaches an ultimate state of decondensation by the end of G₁ period, when DNA synthesis is initiated.     

A method for preventing sorbitol interference with the determination of inorganic phosphate

A technique is described for preventing interference of sorbitol with the assay of P₁ by modifying the procedure of B. N. Ames (1966, in Methods in Enzymology, E. F. Neufeld and V. Ginsburg, eds., Vol. 8, pp. 115–118, Academic Press, New York). The new method relies on the ability of precipitated protein to bind phosphomolybdate and so allow separation of the P₁ from the soluble sorbitol. The conditions for the formation and precipitation of phosphomolybdate-protein complex and for the subsequent assay of P₁ are described. No unique set of conditions could be found which prevented interference at all sorbitol concentrations tested. Instead, conditions for the elimination of interference by particular sorbitol concentration ranges were established. The application of the procedure to samples containing 0–150 nmol of P₁ and 10–100 μmol of sorbitol is described. Complete recovery of P₁ was achieved after precipitation. Standard plots were linear. Coefficients of variation ranged from 9% with low amounts of P₁ (≤25 nmol) to 2.5% at higher levels (150 nmol). One hundred nanomoles of P₁ gave an absorbance at 700 nm of 0.87. Modifications are described to extend the technique to different sorbitol concentration ranges and other applications of the method are mentioned.     

L'intensité lumineuse,son influence sur la teneur en phosphore des carapaces d'Ostracodes

Actual and fossil shells of ostracodes have beenanalyzed with an electronic microprobe: all of them contain phosphorus. X—pictures teach us that the repartition of this chemical element is homogeneous in all the points of the shell. There is no relationship between phosphorus contents in the shells of ostracodes and salinity. In return, there is a relationship between phosphorus contents and temperature and, chiefly, organic phosphorus contents in the environment. However, it is interesting to observe that the analyzed shells of fresh-water ostracodes contain less phosphorus that the generality of the shells of marine ostracodes. The contents of organic phosphorus, in the biotope, depends on the growth of phytoplancton in the upper layers of water which needs a minimum light intensity.     

Bovine pregnancy and nonreturn rates following artificial insemination using a covered sheath

Contamination transferred into the uterus from external genitalia during artificial insemination (AI) has been hypothesized to cause lowered bovine pregnancy rates (PR). Using aseptic techniques, there is still a possibility of uterine contamination during routine AI. Two experiments were conducted to evaluate the effect of two types of sheath covers (CS) placed over the conventional French Medium Syringe assembly (FMS) used for AI. Their use entailed passing the assembly to the external os of the cervix, pushing the FMS through the CS and manipulating the FMS to the cervical uterine junction in the normal manner. Fifty-six day non-return rate (NRR) in dairy and actual PR in beef cattle were evaluated. In Experiment 1, 30 professional technicians were employed to inseminate 7, 387 dairy cows, while in Experiment 2, six technicians with varying levels of experience inseminated 416 beef cows. Least-squares means for NRR in dairy cattle were 78% using a CS and 79% without. Means for PR in beef cattle were 57% using a CS and 62% without. In Experiment 2, the overall PR was lower in Trial l than in other trials (P<0.05). Since some technicians improved with time, the difference due to trial was attributed to technician variation in gaining experience with a CS. Results indicate that general use of a CS in routine AI of apparently healthy cows will not increase PR.     

Cribra orbitalia as a potential indicator of childhood stress: Evidence from paleopathology,stable C,N, and O isotopes,and trace element concentrations in children from a 17th⿿18th century cemetery in JĿkabpils,Latvia

Cribra orbitalia (CO), or porotic hyperostosis (PH) of the orbital roof, is one of the most common pathological conditions found in archaeological subadult skeletal remains. Reaching frequencies higher than 50% in many prehistoric samples, CO has been generally attributed to a variety of factors including malnutrition (e.g., megaloblastic anemia) and parasitism. In this study, we tested the relationship between CO, trace element concentrations, and stable isotope values (δ¹³C, δ¹⁵N, δ¹⁸O) in subadult skeletons from a 17^th to 18^th century cemetery in the historic town of JĿkabpils, Latvia. A total of 28 subadults were examined, seven of which (25%) showed evidence of CO. Bioarchaeological evidence indicated high mortality for children in this cemetery: half of the burials were subadults under the age of 14, while a third were under the age of four. Life expectancy at birth was estimated to have been only 21.6 years. Trace element concentrations measured by Inductively Coupled Plasma ⿿ Mass Spectrometry (ICP-MS) showed no relationship between presence or absence of CO and levels of manganese, zinc, strontium, barium, copper, cadmium, or lead in the bones (p > 0.05). However, a significant correlation (p < 0.05) was found between the presence of CO and decreased levels of iron. The correlations between CO and decreased levels of copper and lead approached significance (p = 0.056 for both elements). Individuals with CO furthermore displayed significantly lower δ¹⁵N isotope values, suggesting greater consumption of lower trophic level food resources than those unaffected by CO; δ¹³C and δ¹⁸O values, in contrast, showed no significant differences. These results suggest that the prevalence of CO may be related to dietary deficiencies. In this case, low iron levels may also signify a diet low in other key vitamins (e.g., B₉ and B₁₂), which are known to cause megaloblastic anemia.     

Normal Superoxide Dismutase (SOD) Gene in Pregnancy-Induced Hypertension: Is the Decreased Sod Activity a Secondary Phenomenon?

Reactive oxygen species (ROS) have been implicated in the pathogenesis of pregnancy-induced hypertension (PIH). A genetic factor is also thought to be associated with the disease. The aim of the present study was to investigate whether decreased superoxide dismutase (SOD) activity in PIH resulted from gene abnormalities. Fourteen patients with PIH were enrolled in the study. Normal pregnant women and normal nonpregnant women served as controls. Genomic DNA and mRNA were isolated from white cells and subjected to Southern and Northern blot analysis with a 600 bp CuZn-SOD probe. SOD activity was also determined in the white blood cells and red blood cells. The results showed that SOD activity was significantly reduced in patients with PIH compared to both control groups. There were no significant differences in the size of the CuZn-SOD gene and its expression between the patients with PIH and the controls. This study confirmed that there was a decreased SOD activity in PIH but revealed neither major structural changes in the genomic DNA nor mRNA size of CuZn-SOD. Our results suggest that the decreased SOD levels in PIH are not due to abnormalities in the CuZn-SOD gene and are an acquired phenomenon which occurs during the development of the disease.     

Prevalence and possible etiology of dental enamel hypoplasia

Two hundred black and white adult human skeletons and 200 living black and white children from the greater Cleveland area were examined for evidence of enamel hypoplasia. Enamel hypoplasia, present in varying expressings (pits, lines and grooves), was found to be more prevalent in both skeletal samples, than in the living groups. In the majority of cases, sex differences between white and black males and females through time and space are highly significant for all tooth catagories. Regardless of the mechanisms behind it, prevalence of enamel hypoplasia for both white and black group has significantly declined through time. No evidence suggesting specific etiologies responsible for enamel hypoplasia can be found. In the majority of previously published reports, the etiology is still idiopathic. The reduction in the prevalence of enamel hypoplasia in the groups examined through time may be related to improved nutritional conditions and the elimination or decline of childhood diseases that have been implicated in this condition.     

Trace elements under the spotlight: A powerful nutritional tool in cancer

Cancer is the second leading cause of death worldwide. Research on the relationships between trace elements (TE) and the development of cancer or its prevention is a field that is gaining increasing relevance. This review provides an evaluation of the effects of TE (As, Al, B, Cd, Cr, Cu, F, I, Pb, Li, Mn, Hg, Mo, Ni, Se, Si, Sn, V and Zn) intake and supplementation in cancer risk and prevention, as well as their interactions with oncology treatments. Advancements in the knowledge of TE, their dietary interactions and their main food sources can provide patients with choices that will help them to improve their quality of life and therapy outcomes. This approach could open new opportunities for treatments based on the integration of conventional therapies (chemotherapy, radiotherapy, and immunotherapy) and dietary interventions that provide advanced personalized treatments.     

Neonatal incubator or artificial womb? Distinguishing ectogestation and ectogenesis using the metaphysics of pregnancy

A 2017 Nature report was widely touted as hailing the arrival of the artificial womb. But the scientists involved claim their technology is merely an improvement in neonatal care. This raises an under-considered question: what differentiates neonatal incubation from artificial womb technology? Considering the nature of gestation—or metaphysics of pregnancy—(a) identifies more profound differences between fetuses and neonates/babies than their location (in or outside the maternal body) alone: fetuses and neonates have different physiological and physical characteristics; (b) characterizes birth as a physiological, mereological and topological transformation as well as a (morally relevant) change of location; and (c) delivers a clear distinction between neonatal incubation and ectogestation: the former supports neonatal physiology; the latter preserves fetal physiology. This allows a detailed conceptual classification of ectogenetive and ectogestative technologies according to which the 2017 system is not just improved neonatal incubation, but genuine ectogestation. But it is not an artificial womb, which is a term that is better put to rest. The analysis reveals that any ethical discussion involving ectogestation must always involve considerations of possible risks to the mother as well as her autonomy and rights. It also adds a third and potentially important dimension to debates in reproductive ethics: the physiological transition from fetus/gestateling to baby/neonate.     

定坤丹对多囊卵巢综合征患者性激素水平、胰岛素抵抗及妊娠情况的影响

目的:探讨定坤丹对多囊卵巢综合征患者性激素水平、胰岛素抵抗及妊娠情况的的影响。方法:选择2016年5月至2018年5月我院收治的210例多囊卵巢综合征患者,根据随机化原则将其分为两组,每组105例。对照组患者接受达英-35与二甲双胍治疗,研究组在对照组的基础上口服定坤丹治疗。连续治疗3个月后,比较两组治疗前后的性激素水平及胰岛各相关指标的变化。治疗结束后随访1年,比较两组的排卵及妊娠情况。结果:与治疗前相比,两组治疗后的血清睾酮(Testosterone,T)、黄体生成素(Luteinizing hormone,LH)及LH/FSH均明显降低,且研究组以上指标均显著低于对照组(P<0.05)。两组治疗前后的卵泡刺激素(Follicle-stimulating hormone,FSH)水平比较无统计学差异(P>0.05)。与治疗前相比,两组治疗后的空腹胰岛素(Fasting insulin,FINS)、餐后2 h胰岛素(Postprandial 2 hours insulin,2hPINS)及β细胞胰岛素分泌功能(Homeostasis model assessment ofβcell,HOMA-β)均明显升高,胰岛素敏感指数(Homeostasis model assessment-Insulin sensitivity index,HOMA-IS)明显降低,且研究组以上指标较对照组改善更明显(P<0.05)。研究组排卵及成功妊娠率均显著高于对照组(P<0.05)。结论:定坤丹有助于改善多囊卵巢综合征患者性激素水平及胰岛素抵抗,提高排卵及妊娠率。