Structure-activity relationships of hygromycin A and its analogs: protein synthesis inhibition activity in a cell free system

PURPOSE: To differentiate scrotal pathology via MRI by means of a statistical score. METHODS: Between 1989 and 1995 MR images of 105 patients with scrotal pathology were rated retrospectively. In 69 cases linear discriminant analysis was used to differentiate seminoma, teratoma and inflammation. Six MRI attributes were found to be necessary and were weighted with a factor according to their importance. These factors were used to build a score. RESULTS: Criteria found to be important contained the distribution of the variate extensions of elements inside the pathological area and their maximal and minimal signal intensities. Furthermore, the contrast pattern of the pathological area and the visibility of healthy tissue in the pathological testicle was of importance. Seminoma was found to be homogeneous and well demarcated against healthy tissue. Teratoma was also well defined but characterised by inhomogeneous distribution of signal intensities. Inflammation showed diffuse signal increase of the pathological testicle, especially in T1-sequences. Using the score differentiation between tumors and inflammation succeeded in 94.2% between seminoma and teratoma in 89.7%. CONCLUSIONS: Compared to other studies using visual MR image analysis differentiation of scrotal diseases was improved by using a statistical score.     

Intermediate-term outcome of mitral reconstruction in cardiomyopathy

OBJECTIVE: Severe mitral regurgitation is a frequent complication of end-stage cardiomyopathy that contributes to heart failure and predicts a poor survival. We studied the intermediate-term outcome of mitral reconstruction in 48 patients who had cardiomyopathy with severe mitral regurgitation and were operated on between June 1993 and June 1997. METHODS: Ages ranged from 33 to 79 years (63 +/- 6 years) with left ventricular ejection fractions of 8% to 25% (16% +/- 3%). All patients were receiving maximal drug therapy and were in New York Heart Association class III-IV with severe, refractory 4+ mitral regurgitation. Operatively, all 48 had undersized flexible annuloplasty rings inserted, 7 had coronary bypass grafts for incidental disease, 11 had prior bypass grafts, and 11 also had tricuspid valve repair. RESULTS: One operative death occurred as a result of right ventricular failure. Postoperative transesophageal echocardiography revealed mild mitral regurgitation in 7 patients and no mitral regurgitation in 41. There were 10 late deaths, 2 to 47 months after mitral reconstruction. The 1- and 2-year actuarial survivals have been 82% and 71%. At a mean follow-up of 22 months, the number of hospitalizations for heart failure has decreased, and 1 patient has had heart transplantation. Significantly, New York Heart Association class improved from 3.9 +/- 0.3 before the operation to 2.0 +/- 0.6 after the operation. Twenty-four months after the operation, left ventricular volume and sphericity have decreased, whereas ejection fraction and cardiac output have increased. CONCLUSION: Whether this favorable modification of left ventricular function and geometry will persist remains unknown. However, mitral repair for cardiomyopathy with mitral regurgitation allows new strategies for these patients.     

Orthostatic headaches caused by CSF leak but with normal CSF pressures

N1E-115 mouse neuroblastoma cells were injected with a calcium buffer/indicator solution to allow both ratiometric measurement of free calcium concentration and the release of calcium ions upon UV flash. The solution contained sulforhodamine, a marker dye used to estimate the volume injected; fluo-3, a calcium indicator, and NP-EGTA, a high affinity calcium-selective buffer that is converted by UV flash to products with negligible calcium affinity. The calcium increase recorded upon UV irradiation (Delta[Ca2+]i) was small for small injection volumes, increased with larger injection volumes, but approached a plateau at the largest injection volumes. From this relation we estimate the buffering capacity of the cytosol as 1700 ions bound per ion free.     

Distribution of fitness effects caused by random insertion mutations in Escherichia coli

Very little is known about the distribution of mutational effects on organismal fitness, despite the fundamental importance of this information for the study of evolution. This lack of information reflects the fact that it is generally difficult to quantify the dynamic effects of mutation and natural selection using only static distributions of allele frequencies. In this study, we took a direct approach to measuring the effects of mutations on fitness. We used transposon-mutagenesis to create 226 mutant clones of Escherichia coli. Each mutant clone carried a single random insertion of a derivative of Tn10. All 226 mutants were independently derived from the same progenitor clone, which was obtained from a population that had evolved in a constant laboratory environment for 10,000 generations. We then performed competition experiments to measure the effect of each mutation on fitness relative to a common competitor. At least 80% of the mutations had a significant negative effect on fitness, whereas none of the mutations had a significant positive effect. The mutations reduced fitness by about 3%, on average, but the distribution of fitness effects was highly skewed and had a long, flat tail. A compound distribution, which includes both gamma and uniform components, provided an excellent fit to the observed fitness values.     

Induction and detection of apoptosis in human periphery blood T-cells

Freshly isolated, human peripheral blood T (PBT) cells are resistant to induction of apoptosis. In this study, however, we have shown that although small numbers of monocytes (Mo) are required for PBT cells to proliferate optimally in response to mitogenic challenge, a relatively higher percentage of Mo results in a significant decrease in PHA-, but not ConA-induced T-cell proliferation. Interestingly, the decrease in T-cell proliferation correlated to an increase in apoptotic cell death. Moreover, ConA-induced PBT-cells underwent apoptosis in the presence of PHA-pretreated Mo, suggesting a key role of monocyte activation in this system. This apoptosis-promoting effect of activated Mo appeared to depend on contact or close proximity between Mo and PBT-cells, rather than via soluble mediators. Despite an increase in apoptosis by the presence of high numbers of Mo, PHA-stimulated PBT-cells released IL-2 at elevated levels proportional to the increasing numbers of Mo in cultures. They also expressed activation marker CD69 and the IL-2R-gamma chain on the cell surface at comparable or higher levels in the presence of high versus low numbers of Mo. These data suggest that PBT-cells can embark on a normal early phase of activation prior to undergoing apoptosis, thereby providing a model system to study how T-cells are committed to either proliferation or activation-induced apoptosis.     

Binding of Fe3+ ions to halobacterial purple membranes as studied by M?ssbauer spectroscopy

Purple membranes (PM) from Halobacterium were reconstituted with 57Fe ions and investigated by M?ssbauer spectroscopy within the temperature range from 5 to 300 K at the Fe/bacteriorhodopsin (BR) ratio 0.6-300. When the Fe/Br ratio was below 2, Fe3+ bonded to PM mostly as hydroxymonomeric particle [FeOH]2+.5H2O, the apparent charge of the iron ion being two. When the Fe/BR ratio exceeded two, the dimeric form [FeOH](2+)4.8H2O along with a cluster form dominated. The temperature dependences of the mean square displacement show that the mobility of Fe ions changes from the solid-state type to the quasi-diffusional one at temperatures approximately 200 and approximately 230 K for the dimeric or monomeric and cluster iron forms, respectively. The nature of the cation binding sites and their location on the PM surface are discussed. A possible role of the divalent cation binding to PM in the mechanism of BR proton pumping is suggested.     

Effect of a recombinant dimeric tumor necrosis factor receptor on inflammatory responses to intravenous endotoxin in normal humans

To determine the role of tumor necrosis factor (TNF) in lipopolysaccharide (LPS)-induced inflammation, 12 healthy subjects received an intravenous injection with LPS (2 ng/kg) preceded by infusion of either a recombinant human dimeric TNF receptor type II-IgG fusion protein (TNFR:Fc; 6 mg/m2; n = 6) or vehicle (n = 6) from -30 minutes to directly before LPS injection. LPS elicited a transient increase in plasma TNF activity, peaking after 1.5 hours (219 +/- 42 pg/mL; P < .05). Infusion of TNFR:Fc completely neutralized endogenous TNF activity. LPS administration was associated with an early activation of fibrinolysis (plasma concentrations of tissue-type plasminogen activator, plasminogen activator activity, and plasmin-alpha2-antiplasmin complexes), followed by inhibition (plasma plasminogen activator inhibitor type I), changes that were completely prevented by TNFR:Fc. By contrast, TNFR:Fc did not influence LPS-induced activation of coagulation (plasma levels of prothrombin fragment F1 + 2 and thrombin-antithrombin III complexes). TNFR:Fc strongly inhibited endothelial cell activation (plasma levels of soluble E-selectin), modestly reduced neutrophil responses (neutrophilia and plasma concentrations of elastase-alpha1-antitrypsin complexes and lactoferrin), but did not affect the release of secretory phospholipase A2 or lipopolysaccharide-binding protein (P > .05). Infusion of TNFR:Fc only (without LPS) in another 6 normal subjects did not induce any inflammatory response. These data indicate that TNF is involved in only some inflammatory responses to intravenous LPS in humans.     

Couples'' satisfaction with health care service during labor and delivery

In recent years, favorable results have been achieved in patients suffering from azoospermia by microinsemination of spermatozoa taken from their testes. Microinsemination is being introduced in the treatment of patients who have no spermatozoa in their testes via their spermatid and spermatocyte. There are still doubts relating to immature male germ line-cells, such as whether they have, oocyte activating factors, the level of stability of DNA of cell nuclei, and the differences in chromosome numbers. The relatively few cases of gestation using the human spermatid treatment may be due to embryological problems resulting from the instability of nuclear DNA and the insufficiency of oocyte activating factors, which are the result of imperfect microinjection techniques. Improvements in techniques for the clinical application of spermatid and secondary spermatocyte, as well as the collection of basic data to confirm embryological safety are therefore necessary.