Location of fluorotryptophan sequestered in an amphiphilic nanoparticle by rotational-echo double-resonance NMR

Rotational-echo double-resonance (REDOR) 13C NMR spectra (with 19F dephasing) have been obtained of 6-fluorotryptophan complexed by a polymeric amphiphilic nanosphere consisting of a polystyrene core covalently attached to a poly(acrylic acid)-polyacrylamide shell. The REDOR spectra show that aromatic carbons from the polystyrene core and oxygenated carbons in the poly(acrylic acid)-polyacrylamide shell are both proximate to the 19F of 6-fluorotryptophan. Molecular modeling restrained by distances inferred from the REDOR spectra suggests that all of the 6-fluorotryptophans are in the shell but within 10 A of the core-shell interface.     

Digoxin-quinidine interaction in patients with renal failure

Investigations were performed in order to study whether or not quinidine would exert similar effects on the serum digoxin concentration in patients with renal failure as in normal subjects. Fourteen out of fifteen patients showed a significant increase of the serum digoxin level after four days of quinidine application. This indicates, that the quinidine effect is not solely caused by a decrease of the renal digoxin clearance, although nine patients, not being hemodialysed, revealed a correlation between their creatinine clearance and the rise of the serum digoxin concentration after quinidine. As however, the patients on hemodialysis did not show higher digoxin levels than those treated conservatively, it is suggested that the degree of the uremic intoxication might be responsible for the observed correlation.     

Rapid detection of engraftment using T cell receptor gene polymorphism after allogeneic bone marrow transplantation in an alloimmunized child with severe aplastic anemia

A severely alloimmunized boy with aplastic anemia received an HLA-identical BMT from his brother. Despite intensive immunosuppression and large marrow dose, peripheral signs of engraftment occurred only late under G-CSF treatment. With leukocyte counts of < 0.5 x 10(9)/l, chimerism could be proven not only by oligonucleotide fingerprinting but also within 48 h by analysis of polymorphism in the TCR gene family. This rapid and sensitive method to detect engraftment before it became quantitatively evident was important for the clinical management of the patient, obviating the need to search for an alternative marrow donor.     

Deficiency of complex II of the mitochondrial respiratory chain in late-onset optic atrophy and ataxia

Defects of the mitochondrial respiratory chain are increasingly being recognized as an important cause of neurological disease in humans. In many of these patients, the biochemical defect results from an abnormality of the mitochondrial genome. Respiratory chain defects involving complex II, which is entirely encoded by the nuclear genome, are comparatively rare. We report the clinical and biochemical findings in 2 elderly sisters who presented with late-onset neurodegenerative disease. In both patients, a partial deficiency of complex II (approximately 50% of control values) was shown to be present in mitochondria from muscle and platelets. The enzyme defect was not expressed in cultured skin fibroblasts or immortalized lymphocytes. There was an overexpression of the 70-kd flavoprotein subunit in muscle mitochondria from both patients, although we showed that this subunit is present in normal amounts in mitochondrial membranes. Our studies highlight the diversity of the clinical presentation of respiratory chain disease and that complex II deficiency should enter the differential diagnosis of certain patients with late-onset neurodegenerative disease.     

The diagnostic utility of HASTE MRI in the evaluation of acute cholecystitis. Half-Fourier acquisition single-shot turbo SE

OBJECTIVE: To investigate the incidence of complications in the use of assisted reproductive technology in the management of infertile couples. DESIGN: Retrospective study. SETTING: The Egyptian IVF & ET Center, Maadi, Cairo, Egypt. PATIENT(S): Two thousand nine hundred twenty-four patients underwent IVF-ET or intracytoplasmic sperm injection (ICSI) in 3,500 cycles. INTERVENTION(S): IVF-ET, ICSI, ejaculate sperm, epididymal sperm aspiration, and testicular sperm extraction. MAIN OUTCOME MEASURE(S): Complications of the procedure and complications of pregnancy in 702 patients. RESULT(S): Fifteen hundred ovum pickups for IVF-ET and 2,000 ovum pickups for ICSI were performed. Clinical pregnancy occurred in 1,078 patients (30.8%). Four groups of complications were identified. Complications of the procedure occurred in 291 patients (8.3%). Complications of pregnancy included ectopic pregnancy in 1.9%, heterotopic pregnancy in 0.2%. abortion in 20.6%, multiple pregnancy in 28%, pregnancy-induced hypertension in 10%, preterm labor in 21.5%, low birth weight in 30.5%, and intrauterine death in 2%. Coincidental complications occurred in five patients (0.15%). Other complications that were difficult to measure included psychological breakdown and socioeconomic problems. CONCLUSION(S): Assisted reproductive technology is effective for the management of infertility and has an acceptable incidence of complications. Complications rarely endanger the life of the patient. When this line of treatment is offered, the indications should be definitive. Patients should be monitored properly and measures should be taken to minimize the incidence of complications.     

Precipitation in rapidly solidified Al-Mn alloys

Precipitation at 450 °C was studied in melt-spun ribbons containing up to 15 wt pct Mn in solid solution in Al. The as-spun ribbons were microsegregation-free at compositions up to 5 wt pct Mn, but in more concentrated alloys a cellular microstructure was present. Upon annealing, four precipitate phases are observed, some of them being found preferentially on cell boundaries and others being found within the cells. Al₆Mn, G, and the Gℍ phase can coexist for long times at 450 °C, but the G phase appears to be slightly more stable. A less stable T phase was detected in Al-5 wt pct Mn foils following short annealing periods. The supersaturation of the Al matrix can persist for many hours in alloys containing up to 3 wt pct Mn, but is essentially gone after 1 hour in alloys with 5 wt pct Mn or more. On leave at the Center for Materials Research, The Johns Hopkins University, Baltimore, MD 21218. R.J.     

Studies on the permeation of hydrogen and tritium in nuclear process heat installations

To realistically evaluate the important problems of hydrogen and tritium permeation in nuclear heated high temperature systems, estimates are made, among others, on the basis of the authors preliminary experimental data. Steam-methane reforming is used as the key process. The results show that oxide layers can decrease the hydrogen permeation rate by more than two orders of magnitude and that not only the oxidation potential and temperature but also the water partial pressure may be essential for the formation and possibly the structure of oxide layers, and consequently for the permeation rate. The consequences of the experimental data for the permeation of tritium are also discussed. The available empirical data and results of the measurements discussed here still contain large uncertainties. It will therefore be necessary to carry out, under as realistic conditions as possible, a broad parameter study of heat exchanger materials which are seriously considered for use in nuclear process heat installations.