Implications of maternal serum alpha-fetoprotein elevation caused by transabdominal and transcervical CVS

Of 2882 women allocated to either transabdominal CVS (TA) or transcervical CVS (TC) at two large obstetric centres in Denmark, 2707 had blood samples drawn before and 30 min after CVS for maternal serum-alpha-fetoprotein (MSAFP) measurement. 2535 of these women had cytogenetically normal pregnancies and 2091 of them went on to have samples drawn at the 18–20 week follow-up. Post-procedure MSAFP values were correlated to the biopsy method used, with mean MSAFP values significantly higher after TA than TC, 33 and 15 kU/l, respectively (P<0·001). Following TA procedures, 18 per cent of cases had feto-maternal transfusion higher than 0·1 ml; this occurred in only 5 per cent of TC cases. MSAFP levels were associated with spontaneous fetal loss in the TA group but not in the TC group. TC, however, was followed by more losses than TA. The post-CVS MSAFP value was positively correlated with the amount of villi aspirated. The difference in post-procedure elevation in MSAFP 30 min later (average 18 kU/l higher for TA than for TC) was not reflected in raised levels at the 18–20 week follow-up. Study medians at mid-trimester did not differ from reference group medians established from a group of singleton pregnancies with sonographically determined gestational age who did not experience invasive procedures and delivered normal infants. Our findings suggest that CVS does not compromise mid-trimester MSAFP for screening for neural tube defects (NTDs). Extremely high mid-trimester MSAFP values in the TC group could predict imminent loss.     

Molecular cytogenetic analysis of term placentae suspected of mosaicism using fluorescence in situ hybridization

In first-trimester chorionic villus sampling (CVS) for prenatal diagnosis, abnormal chromosomal findings, such as mosaicism, trisomies, or suspect abnormal karyotypes, are found more frequently than at amniocentesis. The fact that these chromosomal abnormalities do not always reflect the fetal karyotype but may be restricted to the placenta is a major problem in diagnosis and counselling. In this paper we present the results of fluorescence in situ hybridization (FISH) studies on interphase nuclei of three term placentae investigated because of false-positive findings at first-trimester CVS. The chorionic villi of the first case showed a mosaic chromosome pattern involving a trisomy 10 cell line and a normal cell line, those of the second case a total trisomy 8 cell line, while in the third case a complete monosomy X was found. Follow-up amniocentesis in each of these three cases revealed a normal karyotype. By using FISH, we were able to confirm the presence of the aberrant cell lines, which were all confined to one part of the placenta. FISH on interphase nuclei allows the investigation of large numbers of cells for the existence of numerical chromosome aberrations in a quick and reliable way.     

First-trimester diagnosis of menkes disease: Intermediate copper values in chorionic villi from three affected male fetuses

Chorionic villus samples with copper contents of 1·91, 4·2, 5·6, and 6·3 ng/mg were observed in four cases with male karyotypes. These values were outside the range for unaffected males (0·30–0·85 ng/mg), and three of them were outside the control range (0·20–2·39 ng/mg). But these three values were below the values previously observed for affected Menkes fetuses (12·0–24·8 ng/mg). Follow-up by ⁶⁴Cu uptake studies on the amniotic fluid cells was performed in three of these cases. A combination of ⁶⁴Cu uptake and chase experiments on the amniotic fluid cells showed more convincingly than ⁶⁴Cu uptake per se the direct copper values of 4·2 and 5·6 ng/mg to correspond to affected fetuses. Amniotic fluid cells from the male fetus with the CV copper value of 1·9 ng/mg showed normal results. The CV copper value of 6·3 ng/mg was considered pathognomonic for Menkes disease. The pregnancy was terminated, and the diagnosis was confirmed on fetal fibroblasts. Maternal deciduum prepared from the placentae showed in one of the cases with an affected fetus copper values ranging from 1·5 to 5·7 ng/mg. In six additional diagnostic cases, the copper content was determined in both CV samples and maternal deciduum. In three of these cases with normal CV sample copper, maternal decidua values of 4·85–7·8 ng/mg copper were observed. These results show that maternal deciduum contamination of a CV sample could cause a false-positive diagnosis.     

First trimester prenatal diagnosis of haemophilia A: Two years' experience

We evaluated the feasibility, reliability, and acceptability of prenatal diagnosis of haemophilia A by DNA analysis of chorionic villi. Twenty-two women at risk to transmit the abnormal gene were referred for prenatal diagnosis, two of them twice. Two of the 22 women appeared to be non-carriers by DNA analysis. In one of these women, the results were known only after chorionic villus sampling had been carried out. Thirteen of the twenty carriers were heterozygous for an intragenic (Bell or Xbal) marker; six women were only heterozygous for the extragenic DXS52 (Stl4) locus. One of the women was homozygous for all the presently known DNA markers within or closely linked with the factor VIII locus. Twelve of the 22 fetuses at risk were male, ten were female. Seven of the 12 male fetuses were shown to be affected and were subsequently aborted. Four male fetuses appeared to be not affected. In one case, the diagnosis was made by use of an extragenic marker. The woman rejected fetal blood sampling to confirm the diagnosis. After birth, a normal factor VIII level was found in three of the four cases. The fourth pregnancy is still continuing. In one of the 12 male fetuses, no diagnosis at the gene level was possible. DNA analysis is expected to provide maximum certainty as to the phenotype of the fetus for approximately 60 per cent of the women; for another 37 per cent a rate of misdiagnosis of 4–5 per cent applies. In only 3 per cent of the cases will no diagnosis at the gene level be possible as yet. The new possibility of a prenatal diagnosis in the first trimester of pregnancy enabled some of these women to have a family of their own and was appreciated in particular by the women who underwent fetoscopy in an earlier pregnancy.     

Maternal serum alfa-fetoprotein levels in the pregnancy complicated by hypertension

Maternal serum alpha-fetoprotein (MSAFP) was determined in patients 33 to 40 weeks pregnant, and the results were analysed with consideration of the presence and quality of hypertensive disease that complicated many of the pregnancies. Patients with incompletely controlled hypertension had significantly higher MSAFP levels than control patients with pregnancies uncomplicated by any risk factor. MSAFP elevation was greatest in pre-eclampsia (301·6 ± 147·6 kU/L, n = 35) > chronic hypertension with superimposed pre-eclampsia (240·4±74.7 kU/L, n = 30) > chronic hypertension (204·1± 105·3 kU/L, n=141). Each was significantly increased (P< 0·0001) over control pregnant patients' levels (104·3 ± 38·8, n= 187). At each gestational week from 33 weeks to term, MSAFP of combined hypertensive women was significantly greater than corresponding control levels (P< 0·003 to < 0·000l). The magnitude and time of onset of MSAFP increase may indicate severe fetal distress.     

Silvery mole-rats (<Emphasis Type="Italic">Heliophobius argenteocinereus</Emphasis>, Bathyergidae) change their burrow architecture seasonally

Little is known about seasonal changes in burrowing activity and burrow architecture in subterranean African mole-rats (Bathyergidae, Rodentia). The solitary genus Heliophobius is the least known genus of this family. We examined burrow systems of the silvery mole-rat ( Heliophobius argenteocinereus) in Malawi in two periods of the dry season. Burrow pattern was influenced by the time of the year, becoming more reticulated at the peak of the dry season when soil was dry and hard. Overall digging activity did not cease during the dry season; yet burrowing strategy changed and the soil was deposited in tunnels rather than transported to mounds. The length of burrow systems was correlated with the body mass of the respective occupants. In spite of their solitary habits – and contrary to the prediction of the aridity food-distribution hypothesis – silvery mole-rats are able to occupy poor habitats with low food supply.     

水生生态系统中的氮

从淡水到河口、沿海和海水系统的连续统一体中,水生生态系统对营养富集和营养比变化的反应各不相同.尽管在淡水系统里,人们认为磷是浮游植物生产的限制性营养元素,但大气中氮的影响和它对淡水酸化所起的作用却可以是有害的.从河口到海岸带的连续统一体中,随着盐的梯度和季节不同,在氮、磷、硅之间出现多元的营养限制,但是,一般认为氮是浮游植物生物量积累的主要限制性营养元素.在氮和磷通量、浮游植物初级生产及渔业产量之间有确切的、非线性的正相关关系.流向河口.海岸和海洋系统的营养负载超过了营养富集后生产活动的同化能力,以及水质发生恶化时,存在着各种阈值.其影响包括有害和有毒藻类的滋生、混浊度增加,随后是沉水植物消失、缺氧、生态系统功能瓦解、栖息地丧失、生物多样性丧失、食物网变换,以及捕捞渔业的损失.     

The effect of queen pheromones on worker honey bee ovary development

We report results that address a long-standing controversy in honey bee biology, the identity of the queen-produced compounds that inhibit worker honey bee ovary development. As the honey bee is the only organism for which identities have been proposed for any pheromone that regulates reproduction, the resolution of its identity is of broad significance. We examined the effects of synthetic honey bee queen mandibular pheromone (QMP), four newly identified queen retinue pheromone components, and whole-queen extracts on the ovary development of caged worker bees. The newly identified compounds did not inhibit worker ovary development alone, nor did they improve the efficacy of QMP when applied in combination. QMP was as effective as queen extracts at ovary regulation. Caged workers in the QMP and queen extract treatments had better developed ovaries than did workers remaining in queenright colonies. We conclude that QMP is responsible for the ovary-regulating pheromonal capability of queens from European-derived Apis mellifera subspecies.     

Effects of distillery waste on the performance of Cicer arietinum L

The impact of distillery effluent in various concentrations (1, 2.5, 5, 10, 25, 50, 75 and 100%) on the seed germination, Speed of Germination Index, growth behaviour, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and the seed protein content of Cicer arietinum L. plants was investigated. The percentage and speed of germination of seeds were increasingly retarded with increase in effluent concentration and at 100% concentration there was no germination. The seedlings exhibited maximum shoot length at 5% concentration and maximum root length at 2.5% concentration. The values of root and shoot lengths, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and seed protein content in pot plants exhibited a gradual increase from the control up to 5% concentration and decreases at higher concentrations. The very high BOD load and the presence of excessive concentrations of soluble salts could be responsible for the toxicity of the effluent. The effluent at up to 5% concentration was, however, beneficial for the overall growth parameters studied and can thus be used as a liquid fertilizer.     

Simulation of pesticide runoff at Rosemaund Farm (UK) using the SoilFug model

A validation exercise of the SoilFug model using field runoff data from Rosemaund Farm (UK) is described. A comparison has been made of modelled and measured concentrations of several pesticides in surface water and soil during and after specific rain events following application. The field experiments were designed to obtain data on rainfall, outflows of water, pesticide application rates and concentrations in soil and water. The results were satisfactory for the undissociated pesticides (atrazine, carbofuran, dimethoate, isoproturon, lindane, simazine and trifluralin), whose concentrations in water were mostly predicted within an order of magnitude of measured data. The results for the dissociated pesticides (dichlorprop, MCPA, mecoprop) were less satisfactory, giving generally much higher predicted concentrations in water. The use of the SoilFug model is suggested for the calculation of predicted environmental concentrations (PECs) in water, since it generally produces acceptable results from a relatively small set of input data, most of which is generally available.