Observations of pressure anisotropy effects within semi-collisional magnetized plasma bubbles.

Magnetized plasma interactions are ubiquitous in astrophysical and laboratory plasmas. Various physical effects have been shown to be important within colliding plasma flows influenced by opposing magnetic fields, however, experimental verification of the mechanisms within the interaction region has remained elusive. Here we discuss a laser-plasma experiment whereby experimental results verify that Biermann battery generated magnetic fields are advected by Nernst flows and anisotropic pressure effects dominate these flows in a reconnection region. These fields are mapped using time-resolved proton probing in multiple directions. Various experimental, modelling and analytical techniques demonstrate the importance of anisotropic pressure in semi-collisional, high-ß plasmas, causing a reduction in the magnitude of the reconnecting fields when compared to resistive processes. Anisotropic pressure dynamics are crucial in collisionless plasmas, but are often neglected in collisional plasmas. We show pressure anisotropy to be essential in maintaining the interaction layer, redistributing magnetic fields even for semi-collisional, high energy density physics (HEDP) regimes.

Developing and testing a system to improve the quality of heparin anticoagulation in patients with acute cardiac syndromes.

We have taken a stepwise approach to improving the dosing of continuous intravenous heparin in patients with acute coronary syndromes. Our primary objective was to use computer modeling to develop a nomogram for managing heparin therapy and to put in place a continuous quality monitoring system to evaluate the nomogram's effectiveness. We prospectively collected data on 41 patients with unstable angina or myocardial infarction who were treated with heparin. Their response to heparin was computer modeled and the dose to achieve an activated partial thromboplastin time (aPTT) ratio of 2.0 was established. This dose was regressed against all demographic characteristics to establish predictors of heparin dose (phase I). The regression formula was used prospectively in 110 patients to initiate the infusion rate of heparin and a bolus dose to achieve an aPTT ratio of 2.5. Subsequent dosage adjustments were achieved by computer modeling the patient's aPTT response (phase II). A nomogram was developed that simulated the decisions achieved using computer-assisted methods. This was retrospectively tested and then prospectively tested in 50 patients using nursing staff (phase IV). The nomogram was then made generally available (phase IV) and has been tested in an additional 310 patients. Phase I: Of the original 41 patients, 32% of the aPTT ratios were in the therapeutic range, 36% were supratherapeutic, and 32% were subtherapeutic after the first 24 hours. Phases II and III resulted in 85% of the aPTT ratios between 1.5 and 2.5 at 24 hours. Phase 4 had similar results in 310 patients. The use of computer-assisted or a computer-generated nomogram to adjust heparin therapy results in better control of heparin therapy than using standard methods.

Localized facial flushing in infancy. Auriculotemporal nerve (Frey) syndrome.

BACKGROUND: Patients with auriculotemporal nerve syndrome (Frey syndrome) have facial flushing, sweating, or both localized to the distribution of the auriculotemporal nerve that occurs in response to gustatory stimuli. In adults, the syndrome usually results from surgical injury or trauma to the parotid gland. The condition is rare in infants, but usually manifests during infancy with the introduction of solid food, thus leading to the misdiagnosis of food allergy by physicians unfamiliar with the syndrome. OBSERVATIONS: We describe 8 children with auriculotemporal nerve syndrome who manifested with flushing only. The reaction was erroneously attributed to food allergy in most cases. Six of the 8 patients were delivered with forceps assistance. The remaining 2 patients, with disease onset during the first 3 months of life, had bilateral involvement without known trauma. CONCLUSIONS: Auriculotemporal nerve syndrome may manifest during infancy as flushing with eating food. In contrast to the syndrome in adults, gustatory sweating is rarely associated. The known use of forceps to assist in the delivery of at least 14 of the 28 previously reported pediatric cases and in 6 of our 8 patients suggests that trauma to the parotid region may be responsible for the condition in most infants, as it is in adults. Auriculotemporal nerve syndrome in infancy should be recognized as a benign condition that often resolves spontaneously. Treatment is ineffective and unnecessary.

Dermatoses in newborns.

Benign dermatoses in newborns must be distinguished from more serious disorders with cutaneous manifestations. Erythema toxicum neonatorum, transient neonatal pustular melanosis, sucking blister, miliaria and mongolian spots are among the many benign skin conditions that can occur in newborns. Recognition of these dermatoses allows the physician to proceed appropriately, reassure the parents and initiate further evaluation or treatment as necessary. To avoid adverse sequelae, special attention must be given to more persistent conditions and those with the potential for complications or malignant transformation. Consultation with a pediatric dermatologist, a plastic surgeon or a neurosurgeon may be necessary.

Extranodal spread of anaplastic large cell (CD30+) lymphoma presenting as a cutaneous perivascular infiltrate.

Cutaneous lesions of anaplastic large cell (CD30+) lymphoma (ALCL) typically present as solitary or multiple ulcerated nodules. This tumor is histologically characterized by a diffuse dermal and sometimes subcutaneous infiltrate composed of bizarre, pleomorphic, neoplastic cells that may be occasionally multinucleated. We report a case of extranodal spread of ALCL to the skin in a 2 1/2-year-old boy presenting as a widespread papular eruption that on biopsy showed lymphoma restricted to the perivascular and periadnexal dermis.

Sexually transmitted diseases in neonates and infants.

With the current resurgence of sexually transmitted diseases (STDs), familiarity with the clinical manifestations of STDs in neonates and infants is essential to minimize the tragic consequences. The recognized routes of transmission of the diseases include transplacental, intrapartum, and postpartum exposure. This discussion will be confined to infections caused by syphilis, herpes simplex virus, human papillomavirus, gonorrhea, and chlamydia emphasizing clinical aspects in this population.

Cutaneous Histoplasma capsulatum in a nonimmunocompromised patient with previously treated cutaneous Mycobacterium kansasii.

This report describes a black woman with a history of cutaneous Mycobacterium kansasii responsive to antituberculous drugs. A culture several years later of cutaneous lesions was also positive for Histoplasma capsulatum. Both cutaneous diseases are rare and most often occur in immunocompromised hosts. There is no known association between these two diseases. This patient may have an as-yet unidentified immunodeficiency that predisposes her to these rare infections. Her case emphasizes the importance of repeat biopsy for atypical skin lesions.

Transient porphyrinemia in a liver transplant recipient.

We report a case of acquired porphyrinemia in a liver transplant recipient. Thrombosis of the portal vein and hepatic artery led to massive necrosis of the patient's first donor liver, necessitating its removal. After an 18-hour anhepatic period, a second donor liver was transplanted. During this interval, the patient was warmed with an infrared heat lamp that emitted bright visible light. Following the anhepatic period, a photodistributed cutaneous erythema was noted. The level of total serum porphyrins during the anhepatic period was significantly elevated at 1.548 mumol/L (normal, less than 0.018 mumol/L). Fractionation showed that the levels of the hydrophobic porphyrins, coproporphyrin and protoporphyrin, were elevated, while the levels of the hydrophilic porphyrins remained normal. Following the successful second liver transplantation, the patient's porphyrin levels declined. This is the first reported case of acquired porphyrinemia in a liver transplant recipient.

Treatment of sickle cell leg ulcers with pentoxifylline.

A 58-year-old black man with leg ulcers of 43 years duration responded to pentoxifylline 400 mg tid in 8 months. The ability of pentoxifylline to increase erythrocyte flexibility and decrease blood viscosity was the basis for our use of this agent. Oral pentoxifylline may be a useful adjunct in healing sickle cell leg ulcers and preventing their recurrence.

Whole-abdominal radiotherapy for patients with minimal residual epithelial ovarian cancer.

Sixteen patients with advanced epithelial ovarian cancer who were treated with cytoreductive surgery followed by multiagent chemotherapy were found to have residual tumor masses less than 2 cm in greatest diameter at reexploration and were treated with whole-abdominal radiation (19-31 Gy). Thirteen patients also received pelvic boosts to a total pelvic dose of 41-53.7 Gy. Radiotherapy was completed in all but 2 patients after treatment delays in 7 patients. Early treatment complications included myelosuppression in 11 patients, diarrhea in 3, and a self-limited small bowel obstruction in one. Delayed complications were severe and included 9 patients with radiation enterocolitis, 8 of whom required intestinal resection or diversion. One additional patient with radiation cystitis required instillation of formalin to control bleeding. Two patients are without evidence of disease 28 and 30 months following radiotherapy, while the remaining 14 patients have recurred after a median progression-free interval of 9 months (range 1-30 months). All patients who recurred failed within the treatment field and died of cancer after a median interval of 19 months following radiotherapy and 9 months after documentation of progression. These data suggest that few patients with persistent ovarian cancer following surgery and chemotherapy will be salvaged with radiotherapy.