SIOP Working Committee on psychosocial issues in pediatric oncology: guidelines for communication of the diagnosis

A 44-year-old man with a St. Jude mitral valve was admitted because of progressive pulmonary edema. He was diagnosed with prosthetic heart valve thrombosis (PHVT) based on the findings of "muffled" prosthetic valve clicks. Doppler echocardiographic evidence of severe mitral stenosis and transesophageal echocardiographic evidence of limited mitral valve motility. Because the patient hesitated to undergo our recommended surgical treatment, he was immediately treated with intravenous recombinant tissue plasminogen activator (100 mg over 3 h) followed by heparinization. Two hours after the thrombolytic therapy, the prosthetic valve clicks became clearly audible and his congestive symptoms were dramatically improved. Follow-up echocardiography no longer-showed significant mitral valve obstruction. A transient cerebral ischemic attack occurred at the end of thrombolytic therapy but there were no neurologic sequalae. The patient, on warfarin therapy, was well at follow-up 8 months after discharge. Surgical intervention has long been the standard therapy for patients with PHVT. Our case experience suggests that thrombolytic therapy may be considered as an effective alternative to surgical intervention for selected patients with PHVT. In this report, we also review the current literature regarding the indications, effectiveness and safety of thrombolytic therapy in PHVT.     

A future for entertainment-defense research collaboration

In 1997, the National Research Council (NRC) issued a report that specified a joint research agenda for defense and entertainment modeling and simulation. This report showed the excellent opportunities for synergy between the entertainment and defense industries. For years, they have been solving similar problems for very different application areas. While those two communities' opposing cultures have been difficult to reconcile, recent efforts have proven promising. The looming question is whether the military sector can follow the leaping technological pace in the entertainment sector. That pace indicates tremendous growth in the entertainment industry, which will be coupled with continued technological innovation. The article shows how those advances will be equally vital for future defense applications, thereby demonstrating the importance of continued and increased defense-entertainment collaboration     

Book reviews

Women, Human Settlements and Housing. by Moser, C. and Peake, L. London: Tavistock, 1987. £25.00 cloth, £10.95 paper.

Science and the Home. by Doreen Yarwood London: Batsford, 1987. 184pp. £9.95 paper.     

Evaluation of LabChip technology for GMO analysis in food

Ongoing technological advances permit the development of new scientific strategies for bio-analysis. The work described here sought to compare a traditional agarose slab gel electrophoresis method combined with digital image analysis against a new microfluidic capillary electrophoresis system (LabChip^TM, Agilent Technologies) to assess their relative performance in the quantitative analysis of polymerase chain reaction (PCR) products. The comparative strategy exploited methodology for providing quantitative genetically modified organism (GMO) determinations in food samples and demonstrated that the LabChip^TM system offered improvements in quantitation accuracy, objectivity and ease of use.     

The influence of modified intermetallics and Si particles on fatigue crack paths in a cast A356 Al alloy

Mechanical fatigue tests were conducted on uniaxial specimens machined from a cast A356-T6 aluminium alloy plate at total strain amplitudes ranging from 0.1 to 0.8% ( R = − 1). The cast alloy contains strontium-modified silicon particles (vol. fract. ~6%) within an Al–Si eutectic, dispersed α intermetallic particles, Al₁₅ (Fe,Mn)₃ Si₂ (vol. fract. ~1%), and an extremely low overall volume fraction of porosity (0.01%). During the initial stages of the fatigue process, we observed that a small semicircular fatigue crack propagated almost exclusively through the Al–1% Si dendrite cells. The small crack avoided the modified silicon particles in the Al–Si eutectic and only propagated along the α intermetallics if they were directly in line with the crack plane. These growth characteristics were observed up to a maximum stress intensity factor of ~ K trmax = 7.0 MPa m^1/2 (maximum plastic zone size of 96 μm). When the fatigue crack propagated with a maximum crack tip driving force above 7.0 MPa m^1/2 the larger fatigue crack tip process zone fractured an increased number of silicon particles and α intermetallics ahead of the crack tip, and the crack subsequently propagated preferentially through the damaged regions. As the crack tip driving force further increased, the area fraction of damaged α intermetallics and silicon particles on the fatigue fracture surfaces also increased. The final stage of failure (fast fracture) was observed to occur almost exclusively through the Al–Si eutectic regions and the α intermetallics.     

ACP Broadsheet No 152: March 1998. Clinical implications of plasma homocysteine measurement in cardiovascular disease

Enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion (AGID) are the most widely used serological tests for Maedi-Visna diagnostics. The purpose of the present study was to develop an indirect whole virus ELISA and an immunodiffusion test and compare their sensitivity. A total of 747 ovine serum specimens were analysed for antibodies against this ovine lentivirus. The number of positive results in the ELISA was 430 (57.56%). In the AGID test, a positive result was found in 380 samples (50.87%). In the group of discordant results 78 (10.4%) samples tested positive by the ELISA and negative by the AGID test and 28 sera (3.7%) were found to be positive by the AGID test and negative by the ELISA. The data in this report show the ELISA to be more sensitive than the AGID test, but accurate serological diagnostics should be based on a combination of the two tests.     

Effects on performance, tissue integrity, and metabolism of vitamin E supplementation for beef heifers fed a diet that contains gossypol

We conducted an experiment for 112 d with yearling beef heifers to evaluate the effects of cottonseed meal (CSM) fed with various concentrations of vitamin E on hematological and tissue components. Heifers were assigned randomly to four treatments, with eight heifers per treatment. The treatments consisted of the following dietary supplements: 1) CON, based on soybean meal with 30 IU vitamin E/kg; 2) GOS, based on CSM with 30 IU vitamin E/kg; 3) G+2E, based on CSM with 2,000 IU vitamin E x animal(-1) x d(-1); and 4) G+4E, based on CSM with 4,000 IU vitamin E x animal(-1) x d(-1). Supplements based on CSM provided 4.5 g of free and 50.5 g of total gossypol x animal(-1) x d(-1). The total gossypol present in the supplements was 29.1% of the negative isomer (-) and 70.9% of the positive isomer (+). Blood samples were collected at the start of the experiment and every 2 wk thereafter up to 16 wk. There was a time x treatment interaction (P<.01) for plasma alpha-tocopherol ( alpha-T) concentration; however, feeding gossypol did not decrease plasma alpha-T. Weight gain, retinol palmitate, retinol, beta-carotene (beta-C), hemoglobin, and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P<.05) in gossypol-fed animals; however, vitamin E supplementation lowered EOF (P<.05). Heifers fed the supplements GOS, G+2E, and G+4E had greater (P<.01) plasma (-)-, (+)-, and total gossypol than heifers fed CON from Collection 2 to the end of the experiment. There was a treatment effect (P<.05) on vitamin E and gossypol concentrations in different tissues, with no effect (P>.05) for trace minerals (Cu, Zn, Fe, and Se). Vitamin E concentration in tissue increased with increased dietary supplementation of vitamin E. In heart and neck muscle, (-)-gossypol was greater (P<.05) than (+)-gossypol, but the reverse was true for liver. Gossypol decreased in vitro lipid peroxidation of liver homogenate in tissues. Gossypol deposition in tissue was liver > heart > muscle. In summary, gossypol from CSM did not decrease concentrations of antioxidant vitamins, including alpha-T, vitamin A, and beta-C, or have any detrimental effect on performance of beef heifers.     

Creep of granular materials

This paper examines the creep of brittle granular materials subjected to one-dimensional compression. One-dimensional creep tests were performed on aggregates of brittle pasta and compared with the behaviour of sand at much higher stress levels. It was found that for both materials, creep strain is proportional to the logarithm of time. One possible mechanism for creep is particle crushing. However, it is usually difficult to measure changes in the particle size distribution during creep because the fines produced are so small, and the mass of fines is too small to measure accurately unless creep is permitted for a very long time. However, for pasta, the particle fragments produced are large, and it is found that particle crushing does occur during creep for 24 hours. This is consistent with the proposition that the behaviour of all brittle granular materials is essentially the same. A micro mechanical argument is then summarised which predicts that creep strain should be proportional to log time.