Heat shock protein 101 effects in A. thaliana: genetic variation, fitness and pleiotropy in controlled temperature conditions.

The Hsp100/ClpB heat shock protein family is ancient and required for high temperature survival, but natural variation in expression and its phenotypic effects is unexplored in plants. In controlled environment experiments, we examined the effects of variation in the Arabidopsis cytosolic AtHsp101 (hereafter Hsp101). Ten wild-collected ecotypes differed in Hsp101 expression responses across a 22 to 40 degrees C gradient. Genotypes from low latitudes expressed the least Hsp101. We tested fitness and pleiotropic consequences of varying Hsp101 expression in 'control' vs. mild thermal stress treatments (15/25 degrees C D/N vs. 15/25 degrees D/N plus 3 h at 35 degrees C 3 days/week). Comparing wild type and null mutants, wt Columbia (Col) produced approximately 33% more fruits compared to its Hsp101 homozygous null mutant. There was no difference between Landsberg erecta null mutant NIL (Ler) and wt Ler; wt Ler showed very low Hsp101 expression. In an assay of six genotypes, fecundity was a saturating function of Hsp101 content, in both experimental treatments. Thus, in addition to its essential role in acquired thermal tolerance, Hsp101 provides a substantial fitness benefit under normal growth conditions. Knocking out Hsp101 decreased fruit production, days to germination and days to bolting, total dry mass, and number of inflorescences; it increased transpiration rate and allocation to root mass. Root : total mass ratio decayed exponentially with Hsp101 content. This study shows that Hsp101 expression is evolvable in natural populations. Our results further suggest that Hsp101 is primarily an emergency high-temperature tolerance mechanism, since expression levels are lower in low-latitude populations from warmer climates. Hsp101 expression appears to carry an important trade-off in reduced root growth. This trade-off may select for suppressed expression under chronically high temperatures.

Concepts of a Web-based open distributed textbook for the multimodal diagnostics of gastrointestinal tumours with MRI, CT and video-endoscopy addressing students of medicine and students of medical informatics as two different target groups.

Multimodal diagnostics of gastrointestinal tumours with MRI, CT and video-endoscopy is a rapidly changing domain. The education at our universities should overcome the obstacles of traditional learning based on paper media and oral lectures with retention rates of 10-30% only. The paper presents the objectives and the results of the design phase of the project ODITEB1-Open Distributed TExt Book, for Computer-Assisted Instruction in the domain mentioned above. The main objective is to produce an electronic interactive textbook in order to shift education to more efficient learning settings with higher retention rates. The main concepts are 1) three-layer architecture (dynamic case layer, intermediate query layer, static instruction layer) 2) case pool distribution 3) active learners experience (interactive exploration of original image data).

The role of the T-lymphocyte in estrogen deficiency osteopenia.

Our laboratory has previously demonstrated that the T-lymphocyte is critical in the development of cyclosporin A-induced osteopenia in the rat model. A similar state of osteopenia is induced by estrogen depletion in the ovariectomized (OVX) rat, which is the animal model of postmenopausal bone loss. However, the role of the immune system, and particularly the T-lymphocyte, in estrogen deplete osteopenia has not been elucidated. We used the Rowett athymic nude rat as our model of T-lymphocyte deficiency. In this study, the experimental rats were divided into four groups as follows: (1) sham-operated Rowett heterozygous (rnu/+) euthymic rats (control group); (2) OVX Rowett heterozygous (rnu/+) euthymic rats; (3) sham-operated Rowett homozygous (rnu/rnu) athymic nude rats, which are T-lymphocyte deficient; and (4) ovariectomized Rowett homozygous (rnu/rnu) rats. Rats were weighed, and venous blood was taken in weeks 2, 4, and 6 for determination of serum osteocalcin. Serum 1,25-dihydroxyvitamin D (1,25(OH)2D) was determined on the day of sacrifice. Following sacrifice, histomorphometry was performed on double-labeled proximal tibial metaphyses. Flow cytometric analysis of splenic mononu-clear cell isolates stained for OX19-positive (CD5) T-lymphocytes was performed. T-lymphocyte analysis revealed significant reductions in both athymic nude groups, while OVX euthymic rats demonstrated a diminished number of T-cells relative to their sham-operated counterparts. Histomorphometric data indicated that both OVX groups exhibited a significant loss of trabecular volume, with associated increases in indices for bone formation and resorption, with resorption likely outstripping formation, resulting in osteopenia. Serum osteocalcin was significantly elevated in the ovariectomized euthymic group throughout the experimental period compared with the control group (p < 0.01); it was elevated in the ovariectomized athymic group on week 4 only (p < 0.01 vs. control). It appears that the T-lymphocyte may not be an essential component in the pathogenesis of estrogen deficiency osteopenia. The contribution of circulating T-lymphocytes as well as other T-lymphocyte-rich organs needs to be explored further.

Trends in the United States cesarean section rate and reasons for the 1980-85 rise.

The rate of cesarean section delivery in the United States rose from 4.5 per 100 deliveries in 1965 to 22.7 in 1985, and in 1985 an estimated 851,000 live births were cesarean deliveries, according to data from the National Hospital Discharge Survey. This increase has been observed for all ages, and within all regions of the country. The rate for teenagers and mothers aged 20 to 29 was five to six times as high in 1985 as in 1965, and four times as high for mothers aged 30 years and older. Repeat cesareans account for an increasing share of all cesarean deliveries; in 1985 one in three cesareans were repeats. The increase in the cesarean rate of 6.2 percentage points between 1980 and 1985 (from 16.5 to 22.7) was partitioned according to five complications of delivery recorded on hospital discharge records: previous cesarean delivery, breech presentation, dystocia, fetal distress, and all other complications. Nearly half (48 per cent) of the increase was associated with previous cesarean delivery, 29 per cent with dystocia, 16 per cent with fetal distress, 5 per cent with breech presentation, and 2 per cent with all other complications.

Electronic fetal monitoring in relation to cesarean section delivery, for live births and stillbirths in the U.S., 1980.

In the 1980 National Natality and Fetal Mortality Surveys, information about fetal monitoring and type of delivery was obtained from hospitals for a sample of 9,941 live births and 6,386 fetal deaths of 28 weeks' gestation or more. Data in this analysis are weighted to provide national estimates of live births and late fetal deaths that occurred in U.S. hospitals during 1980. Electronic fetal monitoring (EFM) was used for 47.7 percent of live births; 27.2 percent were monitored by Doppler ultrasound only, 10.2 percent by scalp electrode only, 6.3 percent by Doppler ultrasound and scalp electrode only, and 4.0 percent by other methods and combinations. The distribution by type of EFM used was similar for the 42.7 percent of late fetal deaths (also called stillbirths) that were monitored. Variation in the use of EFM for live births and stillbirths is examined according to maternal age, parity, education, race, marital status, income, previous fetal loss, underlying medical conditions, complications of pregnancy, complications of labor, duration of labor, infant birth weight, and length of gestation. Among live births, 17.1 percent were delivered by cesarean section, as were 16.8 percent of stillbirths. The association between fetal monitoring and the primary cesarean section rate (the probability of cesarean section for women who had never had one) for all birth orders and for first births is examined according to characteristics of the mothers and the infants. Factors involved in the consistent association found between fetal monitoring and the primary cesarean section rate are discussed.