Exchange bias and domain evolution at 10 nm scales.

For a fixed 2 µm×2 µm area of a Co/Pt-CoO perpendicular exchange bias system we image the ferromagnetic (FM) domains for various applied fields with 10-nm resolution by magnetic force microscopy (MFM). Using quantitative MFM we measure the local areal density of pinned uncompensated spins (pinUCS) in the antiferromagnetic (AFM) CoO layer and correlate the FM domain structure with the UCS density. Larger applied fields drive the receding domains to areas of proportionally higher pinUCS aligned antiparallel to FM moments. The data confirm that the evolution of the FM domains is determined by the pinUCS in the AFM layer, and also present examples of frustration in the system.

Direct observation of spin-torque driven magnetization reversal through nonuniform modes.

We present time-resolved x-ray images with 30 nm spatial and 70 ps temporal resolution, which reveal details of the spatially resolved magnetization evolution in nanoscale samples of various dimensions during reversible spin-torque switching processes. Our data in conjunction with micromagnetic simulations suggest a simple unified picture of magnetic switching based on the motion of a magnetic vortex. With decreasing size of the magnetic element the path of the vortex core moves from inside to outside of the nanoelement, and the switching process evolves from a curled nonuniform to an increasingly uniform mode.

Time-resolved imaging of spin transfer switching: beyond the macrospin concept.

Time-resolved images of the magnetization switching process in a spin transfer structure, obtained by ultrafast x-ray microscopy, reveal the limitations of the macrospin model. Instead of a coherent magnetization reversal, we observe switching by lateral motion of a magnetic vortex across a nanoscale element. Our measurements reveal the fundamental roles played independently by the torques due to charge and spin currents in breaking the magnetic symmetry on picosecond time scales.

Display of complete life cycle of human papillomavirus type 16 in cultured placental trophoblasts.

Human papillomavirus (HPV) infection is threefold more prevalent in spontaneous abortion specimens compared to elective abortions preferentially targeting the placental trophoblasts in these specimens. Here by using infectious ceplar and Southern blot analysis, we demonstrate that the transfected HPV-16 genome de novo replicates in 3A trophoblasts in culture. Peak DNA replication occurred 9-24 days posttransfection, showing classic DNA forms I, II, and III and an 8-kb monomer band upon DpnI/BamHI digestion. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of mRNA expression revealed that E6 and E2 were significantly expressed by day 9, coinciding with HPV-16 DNA replication. However, significant L1 expression was delayed until day 18. L1 protein expression on day 18, but not day 9, was also confirmed by Western blot analysis. The production of HPV-16 virions was demonstrated by three techniques: the appearance of HPV-16 infectious units coinciding with L1 expression, the neutralization of these infectious units with known neutralizing anti-HPV-16 antibodies, and the appearance of spliced E1-E4 and E6-E7 transcripts (RT-PCR) in normal keratinocyte rafts infected with these trophoblast-produced HPV-16 infectious units. These data suggest that HPV-16 is carrying out its complete life cycle in trophoblasts. Previously, HPVs were known to productively replicate only in differentiating keratinocytes of skin. These findings expand HPV biology, support the hypothesis of a possible link between HPV and some spontaneous abortions, and present a new technology for studying HPV.

A survey of domestic violence in a university emergency department.

OBJECTIVES: To determine prevalence of domestic violence among female patients presenting to the department. METHODS: An anonymous survey distributed to female patients presenting over a 30-day period. RESULTS: Response rate was 12.5% (190 of 1,516). Forty-four percent of respondents reported being a victim of domestic violence in the past Seventy-nine percent knew where to get help, and 64% would report it. Eight percent reported their visit to the department resulted from domestic violence. CONCLUSIONS: Prevalence of domestic violence from the sample was similar to previously reported rates. Physicians and nurses generally inquired when patients presented resulting from domestic violence, but screening rates need improvement.

Primary anaplastic large cell lymphoma of the small intestine.

We describe the clinicopathologic, immunophenotypic, and molecular findings in 4 cases of anaplastic large cell lymphoma (ALCL) arising in the small intestine. All patients were men with acute symptoms of gastrointestinal tract obstruction. The clinical preoperative diagnosis was gastrointestinal carcinoma in 3 cases, and pancreatic carcinoma in 1 case. Histologic examination revealed cohesive aggregates of neoplastic cells, with multiple vesicular nuclei, prominent nucleoli, and abundant amphophilic cytoplasm. There was no clinical or histopathologic evidence of enteropathy. All cases were CD30+, and all showed evidence of T-cell lineage with cytotoxic potential by expression of CD3, CD43, or CD45RO; T-cell intracellular antigen-1; or perforin. One tumor showed p80 and anaplastic lymphoma kinase (ALK) overexpression corroborated by the presence of the t(2:5). One tumor expressed Epstein-Barr virus latent membrane protein. In all cases, the tumor cells were negative for CD20, CD15, CD56, and cytokeratin. Polymerase chain reaction revealed clonal rearrangements of the T-cell receptor gamma-chain gene, without evidence of immunoglobulin heavy-chain gene rearrangement. The diagnosis of primary bowel ALCL is facilitated by immunophenotypic and molecular studies. With 24 months of clinical follow-up, only the patient with the t(2:5)-positive tumor is alive and free of disease, suggesting that p80/ALK overexpression may be a good prognostic indicator.

Hydroxyapatite as a bone substitute.

A bone substitute eliminates the need for autogenous and allogeneic bone grafting, along with the complications unique to each. Coralline hydroxyapatite is a synthetic bone void filler manufactured from marine coral, which has a natural trabecular structure similar to that of cancellous bone. While initial studies have been promising, the use of coralline hydroxyapatite may be limited in the foot and ankle owing to its inherent mechanical weakness and lack of biodegradation. In this retrospective study, 20 patients who received coralline hydroxyapatite implants were reviewed to determine associated complications and host reaction to the material. The results indicate that the material is biologically inert and safe to use as a small-defect filler in low-load applications. Long-term clinical trials are needed to determine the indications for this material in the foot and ankle.

Aortic dissection.

The presentation of aortic dissection in the emergency department may be more subtle than the classic description of a shocked patient with "ripping" chest pain. The epidemiology, variation in presentation, investigation, and management of aortic dissection are reviewed.

Cytokeratin-positive cells in PBSC collections from normal donors and patients with non-epithelial cell-derived tumors.

BACKGROUND: It is possible that post-transplant relapse in patients with breast cancer may result, in part, from residual tumor in the autologous PBSC product. It is unclear from the literature what effect residual breast tumor cells have on clinical outcome and whether purging tumor cells would be beneficial. We hypothesized that lack of standardization of assays for detection of residual breast tumor may be responsible for the inconclusive clinical data. METHODS: We compared two assays routinely for detection of cytokeratin (CK)-positive cells in stem-cell grafts, immunohistochemistry (IHC) and flow cytometry (FCM). The patient population consisted of individuals with breast cancer, non-epithelial cell-derived tumors and normal donors. A rigorous statistical model was developed for evaluation of the data. RESULTS: We found that the IHC assay out-performed the FCM assay. Importantly, both assays detected CK-positive cells in PBSC collections of patients with non-epithelial cell-derived tumors and in normal donors. No distinguishing morphological characteristics could be identified to differentiate potentially malignant from non-malignant CK-positive cells. Due to the inability to distinguish true positive from false positive results, we developed a statistical model to establish a quantitative threshold to discriminate positive from negative samples. Among the patients tested, no clinical outcome differences were detected, regardless of where the threshold of CK-positive cells was set. DISCUSSION: We conclude the more stringent criteria and more specific markers, rather than the presence or absence of CK-positive cells, need to be established to determine the clinical significance of minimal residual disease in autologous breast-cancer

Disseminated intravascular coagulation: clinical and laboratory aspects.

Disseminated intravascular coagulation (DIC) is a complex acquired coagulopathy resulting from excessive thrombin formation. Abnormal tissue factor (TF) expression is a major mechanism initiating DIC in many disorders, including obstetrical complications, sepsis, cancer, and trauma. Numerous laboratory tests are available to monitor DIC, but most patients are adequately managed using only routine hemostasis screening tests, and assays for fibrinogen and D-dimer. Treatment of DIC should focus on reversing the underlying disorder initiating the coagulopathy. Novel treatments are being investigated for treating DIC; many of these experimental modalities target the excessive TF activity that characterizes DIC.

Motorbike injuries in Bermuda: a risk for tourists.

STUDY OBJECTIVE: To describe the incidence of injuries associated with motorbike use in Bermuda and discuss prevention strategies. METHODS: We conducted a population-based study of all incident of traffic accidents involving motorbikes. Demographic characteristics and mechanisms, rates, and outcomes of injury for tourists and residents were compared. RESULTS: We identified 657 cases of road trauma that occurred between July and September 1993. Of these cases, 538 (81.9%) involved motorbikes. The tourist rate of motorbike-related injury was 94.1/1,000 person-years at risk, whereas that of the local population was 16.6/1,000. The injury rate among residents was highest for young males, whereas among tourists it was highest among older persons. The relative risk (RR) of injury for tourists was 5.6 (95% confidence interval [CI], 4.8 to 6.7). Tourists also had an increased risk of fracture (RR, 1.43; 95% CI, 1.22 to 1.67). CONCLUSION: Tourists visiting Bermuda are at high risk of injury from motorbike use, with rates of injury much higher than the local population. Prevention strategies, particularly for older tourists, should be developed and implemented.

Epiglottitis in adults.

Acute epiglottitis has become a disease of adults, probably as a result of immunization of children against Haemophilus influenzae. This article is a review of the literature on epiglottitis, including signs and symptoms, investigation, differential diagnosis, and treatment in the emergency department. The microbiology is discussed and the importance of prophylaxis in exposed persons is stressed.

Telephone advice about an infant given by after-hours clinics and emergency departments.

AIMS: Studies have shown that telephone calls for advice constitute a significant portion of the workload of emergency departments in the United States and the United Kingdom. Reviews of the appropriateness of telephone advice given in emergency departments in the United States indicate that the information given is often inadequate or inaccurate. We performed a study to evaluate the telephone advice given in New Zealand. METHODS: We identified 30 public hospital emergency departments and 20 private accident and emergency clinics. Twenty-six towns and cities were represented. We telephoned each of them and requested advice about the management of a fictitious febrile infant. RESULTS: We were given medical advice by 36 of the centres. In the remaining 14 the caller was referred to an oncall duty doctor or general practitioner for further information. In the 36 departments providing advice, the information was given by a doctor in 5 of the cases, by a nurse in 26, and by a receptionist or unidentified respondent in 5. On average, the caller was asked 3.76 questions about the patient before advice was given. Even if a number of questions were asked, correct advice did not necessarily follow. Thirty five of the advice givers requested the age of the infant, but 16 of them gave inadequate advice despite this knowledge. We judged the advice given to be inadequate in 16 of the 36 institutions that provided it. There was no difference in the standard of advice given by private and public institutions. DISCUSSION: This study demonstrates that there are deficiencies in the quality of telephone advice given by emergency departments and private accident and emergency clinics in New Zealand.

Diverse effects of antiemetics in children.

AIMS: To present cases of dystonic reactions in paediatric patients related to the use of antiemetics and to remind practitioners of the potential hazards of these agents in the paediatric age group. METHOD: Discussion of the presentations of three children at the Middlemore Hospital emergency department with neurological symptoms after exposure to prochlorperazine or metoclopramide and one child with a possible phenothiazine ingestion. RESULTS: These cases illustrate that some physicians are unaware of the potential hazards of antiemetics in children. CONCLUSIONS: Physicians prescribing antiemetics for children presenting with viral gastroenteritis should carefully consider the risks and benefits of these medications. If the drugs are prescribed, instructions about possible side effects should be emphasised so that corrective treatment can be initiated promptly. A full drug history should be obtained on all patients presenting to emergency departments. In addition, the emergency physician evaluating children with unusual neurological symptoms should always consider the possibility of an acute extrapyramidal reaction.

A cutaneous infection with Mycobacterium fortuitum.

We report the case of a 24-year-old man with a cutaneous Mycobacterium fortuitum infection. The investigation and management of this patient are discussed, and literature pertaining to this organism is reviewed. The importance of considering mycobacteria in the pathogenesis of chronic cutaneous disease is stressed.

Preparing stewards for tomorrow. A healthcare system's intern program provides mentors for potential trustees.

Mentors can provide support essential to a person's advancement and growth in a new business or position. Because of the complex and rapidly changing nature of healthcare, mentors can be particularly valuable to persons interested in becoming healthcare facility trustees. Since 1987, the Sisters of Mercy Health System (SMHS), St. Louis, has implemented a comprehensive intern program for potential trustees. Each intern is assigned to a board and a board member mentor at an SMHS facility. The program lasts for two years and includes a didactic component, independent study, clinical experience, regularly scheduled meetings, and issuance of a certificate on completion. Thus far, the interns have been sisters from education, healthcare, social service, or other ministries. They must show abilities crucial for successful trustees (such as listening skills), an appreciation of and strong support for the ministry, and a willingness to commit the time and energy to the program. Mentors chosen for the program also must devote time to orientation and meetings and must assist interns in integrating mission and values into board activities. In addition, mentors help interns identify the focus of present structures and resources and their appropriateness and discuss the trustee's role and responsibilities and dynamics for quality decision making.