Quantitative determination of conformational, dynamic, and kinetic parameters of a ligand-protein/DNA complex from a complete relaxation and conformational exchange matrix analysis of intermolecular transferred NOESY

We report a quantitative analysis of the 13C-edited intermolecular transferred NOESY (inter-TrNOESY) spectrum of the trp-repressor/operator complex (trp-rep/op) with [ul-13C/15N]-L-tryptophan corepressor using a computer program implementing complete relaxation and conformational exchange matrix (CORCEMA) methodology [Moseley et al. (1995) J. Magn. Reson. 108B, 243-261]. Using complete mixing time curves of three inter-TrNOESY peaks between the tryptophan and the Trp-rep/op, this self-consistent analysis determined the correlation time of the bound species (tauB = 13.5 ns) and the exchange off-rate (k(off) = 3.6 s(-1)) of the corepressor. In addition, the analysis estimated the correlation time of the free species (tauF approximately 0.15 ns). Also, we demonstrate the sensitivity of these inter-TrNOESY peaks to several factors including the k(off) and orientation of the tryptophan corepressor within the binding site. The analysis indicates that the crystal structure orientation for the corepressor is compatible with the solution NMR data.     

Glutamate modulation of dendrite outgrowth: alterations in the distribution of dendritic microtubules

Glutamate can both facilitate and inhibit dendrite outgrowth in vitro. The major effects of low levels of glutamate occur only on the dendrites (not the axon) of pyramidal neurons and may be important for modulating dendrite outgrowth during neuronal development in vivo. Cytoskeletal changes resulting from glutamate exposure must underlie these changes in dendrite outgrowth. In the present study, hippocampal neuron cultures were used to measure the outgrowth of both axons and immature dendrites in the presence or absence of 50 microM glutamate. Subsequently, neurons were extracted and fixed for immunofluorescent labeling of microtubules and rhodamine phalloidin labeling of microfilaments. Additionally, neurons were prepared for electron microscopy to examine dendritic microtubules at the ultrastructural level. Glutamate led to increased dendrite outgrowth in the short term (4 hr) and dendrite retraction in the long term (8 hr). After short-term glutamate exposures, no obvious morphological changes occur in either the microtubules or microfilaments. However, longer glutamate exposure causes a decrease in the number of microtubules in the distal region of retracting dendrites, and causes an increase in microtubule number in the dendritic shaft of both retracting and growing dendrites. Thus, the microtubule cytoskeleton may be involved in producing the changes in dendrite outgrowth caused by glutamate exposure.     

Concomitant therapy with anxiolytics or hypnotics and maintenance of initial SSRI therapy

BACKGROUND: Depletion of fat-free mass (FFM) occurs in a considerable number of patients with chronic obstructive pulmonary disease (COPD). OBJECTIVE: The goal of the study was to determine whether dual-energy X-ray absorptiometry (DXA) is an applicable method in the clinical evaluation of body composition in COPD. DESIGN: In a cross-sectional study in 79 COPD patients participating in a pulmonary inpatient program and in 23 healthy volunteers, DXA was compared with deuterium dilution (Deu) in the estimation of FFM. Bone mineral density (BMD), a DXA measurement, was also compared between the 2 groups. RESULTS: FFM(DXA) was highly related to FFM(Deu) in men (R2 = 0.93, P < 0.001) and women (R2 = 0.91, P < 0.001). On average, DXA resulted in higher FFM values than did Deu in COPD patients (3.4 kg; P < 0.001) and in healthy volunteers (2.1 kg; P < 0.001). Furthermore, the intramethod difference in FFM was higher in men than in women in the COPD group (P < 0.05) and in healthy volunteers (P < 0.001). BMD was lower in the COPD group than in the healthy, age-matched volunteers (P < 0.001). In 56% of the COPD patients, there were indications of bone mineral loss, defined as a BMD <1 SD of a matched reference population provided by the software. BMD was <2 SDs in 36% of the COPD patients. CONCLUSIONS: DXA appears to be a suitable alternative method to Deu for assessing body composition and is also of value in identifying bone mineral loss in COPD patients, and is therefore applicable in the clinical evaluation of these patients.     

Hypertrophic cardiomyopathy. Role of Doppler echocardiography in the diagnosis and therapeutic approach

The present study was undertaken with the aim to study the role of isologous and heterologous (buffalo) oviductal cell to co-culture on in vitro development of goat embryos. The oocytes were collected by puncturing the goat ovaries obtained from slaughterhouse. The oocyte recovery rate per ovary was 3.0. The media used for oocyte maturation and embryo development was TCM-199 + 10 percent buffalo estrus serum. A total of 79.8 percent oocytes got matured out of 1056 oocytes. The oocytes were inseminated with epididymal buck spermatozoa capacitated in Brackett and Oliphant media. In group I without oviductal cells co-culture only 13.6 percent matured oocytes cleaved and 3.3 and 0.0 percent reached the morula and blastocyst stage. In group II and III having goat and buffalo oviductal cells the cleavage was 57.6 and 59.2 percent respectively. The percentage of morula, blastocyst and those embryos arrested between 2-16 cells were 26.3, 10.2, 63.5 and 26.6, 8.9 and 64.5 in goat and buffalo oviductal cell groups. The results indicated that the oviductal cell co-culture had a marked effect on cleavage and development of goat IVF embryos. Buffalo oviductal cells can be used well for goat embryo development.     

Skin injury in the operating room

Judge Christian Byk renders service to the Steering Committee on Bioethics of the Council of Europe (CDBI) by proposing a draft of the protocol destined to fill in a gap in international law on the status of the human embryo. This proposal, printed in a previous issue of the Journal of Medical Ethics deserves nevertheless to be questioned on important points. Is Christian Byk proposing to legalise research on human embryos not only in vitro but also in utero?     

Oxylipin formation in fungi: biotransformation of arachidonic acid to 3-hydroxy-5,8-tetradecadienoic acid by Mucor genevensis

STUDY OBJECTIVE: The objectives of the present study were to evaluate the importance of intrapulmonary lymph nodes (IPLNs) in the differential diagnosis of small pulmonary nodules and to review the CT findings of IPLNs. DESIGN: Retrospective analysis of patient records. SETTING: Chest Disease Research Institute Hospital, Kyoto University. PATIENTS: Between January 1991 and May 1996, we examined 26 patients with pulmonary nodular shadows smaller than 1 cm in diameter that could not be diagnosed before surgery. All patients (19 men, 7 women) underwent chest CT (28 to 72 years old; mean, 52.3 years). RESULTS: The pathologic diagnoses were IPLNs in 46.2% (12/26), pulmonary hamartoma in 23.1% (6/26), lung cancer in 11.5% (3/26), pulmonary tuberculoma in 11.5% (3/26), and metastatic lung tumor in 7.7% (2/26). IPLNs were located in the lower lobe in 72%. The characteristic CT findings of IPLNs were a clear border and location close to the pleura. Two of them resembled lung cancer. The CT features in these two IPLNs and in three small lung cancers overlapped. CONCLUSIONS: In the present study, we investigated small nodular shadows <1 cm in diameter and found that IPLNs located underneath the pleura are important to consider in the differential diagnosis of lung cancer. The CT scan findings of IPLNs were not necessarily specific and sometimes resembled those of lung cancer. Because of their location, video-assisted thoracic surgery is useful in making a definite diagnosis.