Biomedical subjects

James Dunn

Publications and source records attributed to James Dunn.

9 recordsLinked to original sources

PubMed2006

Prediction and observation of tin and silver plasmas with index of refraction greater than one in the soft x-ray range.

We present the calculated prediction and the experimental confirmation that doubly ionized Ag and Sn plasmas can have an index of refraction greater than one for soft x-ray wavelengths. Interferometry experiments conducted using a capillary discharge soft x-ray laser operating at a wavelength of confirm that in few times ionized laser-created plasmas of these elements the anomalous dispersion from bound electrons can dominate the free electron contribution, making the index of refraction greater than one. The results confirm that bound electrons can strongly influence the index of refraction of numerous plasmas over a broad range of soft x-ray wavelengths confirming recent observations. The understanding of index of refraction at short wavelengths will become even more essential during the next decade as x-ray free electron lasers will become available to probe a wider variety of plasmas at higher densities and shorter wavelengths.

Journal Article↗

PubMed2006

Discovery of S-[5-amino-1-(4-fluorophenyl)-1H-pyrazol-4-yl]-[3-(2,3-dihydroxypropoxy)phenyl]methanone (RO3201195), an orally bioavailable and highly selective inhibitor of p38 MAP kinase.

A novel class of highly selective inhibitors of p38 MAP kinase was discovered from high throughput screening. The synthesis and optimization of a series of 5-amino-N-phenyl-1H-pyrazol-4-yl-3-phenylmethanones is described. An X-ray crystal structure of this series bound in the ATP binding pocket of unphosphorylated p38alpha established the presence of a unique hydrogen bond between the exocyclic amine of the inhibitor and threonine 106 which likely contributes to the selectivity for p38. The crystallographic information was used to optimize the potency and physicochemical properties of the series. The incorporation of the 2,3-dihydroxypropoxy moiety on the pyrazole scaffold resulted in a compound with excellent drug-like properties including high oral bioavailability. These efforts identified 63 (RO3201195) as an orally bioavailable and highly selective inhibitor of p38 which was selected for advancement into Phase I clinical trials.

Adenosine Triphosphate↗

PubMed2005

Pelvic sidewall adenocarcinoma after definitive therapy for cervical adenocarcinoma in situ.

BACKGROUND: Traditionally, hysterectomy is considered definitive therapy for cervical adenocarcinoma in situ (AIS) in women beyond childbearing. CASE: A 45-year-old gravida 2, para 2 patient presented with cervical dysplasia and on pathology review of the large loop excision procedure cervical adenocarcinoma in situ was diagnosed. She underwent extrafascial hysterectomy and bilateral salpingo-oophorectomy. Final pathology revealed adenocarcinoma in situ with negative margins. Twenty-eight months later, she presented with right lower extremity deep venous thrombosis. A computed tomography (CT) scan of the abdomen and pelvis showed a pelvic sidewall mass. A CT-guided biopsy of the mass was consistent with invasive adenocarcinoma of the endocervical type. She underwent combination therapy with weekly cisplatin and extended field radiation therapy. CONCLUSION: This case depicts another example of the unpredictable nature of cervical AIS. Despite undergoing definitive surgery, a residual focus of disease may remain leading to invasive adenocarcinoma. Close follow-up is required of all patients diagnosed with AIS because the disease is poorly understood.

Adenocarcinoma↗

PubMed2004

Picosecond-resolution soft-x-ray laser plasma interferometry.

We describe a soft-x-ray laser interferometry technique that allows two-dimensional diagnosis of plasma electron density with picosecond time resolution. It consists of the combination of a robust high-throughput amplitude-division interferometer and a 14.7-nm transient-inversion soft-x-ray laser that produces approximately 5-ps pulses. Because of its picosecond resolution and short-wavelength scalability, this technique has the potential for extending the high inherent precision of soft-x-ray laser interferometry to the study of very dense plasmas of significant fundamental and practical interest, such as those investigated for inertial confinement fusion. Results of its use in the diagnostics of dense large-scale laser-created plasmas are presented.

Journal Article↗

PubMed2004

Essential techniques for intraoperative composite endograft (CEG) formation in the treatment of abdominal aortic aneurysm.

The development of an ideal aortic stent graft continues to progress. New devices and techniques are expanding the use of endovascular repair in the treatment of abdominal aortic aneurysms (AAA). We present data with intraoperative composite endograft (CEG) techniques evaluating immediate and short-term compatibility of components and patients outcome. Twenty-five of 66 patients (38%) received intraoperative CEGs for AAA treatment. A total of 50 components were used to treat type I endoleaks, prevent graft limb kinking or treat associated iliac aneurysm. Nine of the components were used to manage type I proximal endoleaks. Forty-one components were used at the iliac limb for distal type I endoleak, hostile iliac anatomy, or graft limb support or to treat an associated iliac aneurysm. Two patients were left with a type I endoleaks at the iliac attachment site on completion of graft placement. With a mean follow-up of 11 months. Two of 25 patients had a type II endoleak at 6 months. One patient had type I endoleak at 1 year follow-up. CEGs are essential to treat endoleaks with a high technical success rate and expand the indications for treating infrarenal AAA. The component's short-term compatibility makes this method of stent graft placement safe.

Aged↗

PubMed2003

Emergence of echovirus type 13 as a prominent enterovirus.

In 2001, increased activity of the rarely detected enterovirus echovirus type 13 (E13) was observed in the United States. This article describes the epidemiologic, clinical, and genetic characteristics of E13 activity in the United States in 2001, compared with E13 activity abroad in 2000-2002. In the United States, E13 accounted for 376 (24%) of the 1584 enterovirus isolates reported in 2001 (29% of the reported isolates had a known serotype), compared with 74 isolates reported during 1970-2000. Five states reported aseptic meningitis outbreaks associated with E13, for a total of 521 cases. All characterized E13 isolates from the United States, Europe, Asia, and Oceania recovered in 2000-2002 were at least 95% identical to each other in VP1 capsid gene sequence, but they were genetically distinct from E13 isolates recovered before 2000. Continued surveillance of enteroviruses is important to alert physicians and public health officials to changes in disease trends and to improve efficiencies of clinical intervention.

Asia↗

PubMed2003

Longitudinal coherence measurements of a transient collisional x-ray laser.

We present what is to our knowledge the first longitudinal coherence measurement of a transient inversion collisional x-ray laser. We investigated the picosecond output of a Ni-like Pd x-ray laser at 14.68 nm generated by the COMET laser facility at the Lawrence Livermore National Laboratory. Interference fringes were generated with a Michelson interferometer setup in which a thin multilayer membrane was used as a beam splitter. We determined the longitudinal coherence for the 4d1S0 --> 4p1P1 lasing transition to be approximately 400 microm (1/e half-width) by changing the length of one interferometer arm and measuring the resultant variation in fringe visibility. The inferred gain-narrowed linewidth of approximately 0.29 pm is a factor of 4 less than previously measured in quasi-steady-state x-ray laser schemes.

Journal Article↗

PubMed2003

Seeding of a cavernous angioma with Mycoplasma hominis: case report.

OBJECTIVE AND IMPORTANCE: To describe a unique case of hematogenous seeding of a cavernous angioma with the commensal organism Mycoplasma hominis. CLINICAL PRESENTATION: A 40-year-old female patient presented with a severe headache and acute left facial nerve palsy. Imaging studies revealed a right frontal mass lesion with characteristics of a cavernous angioma. INTERVENTION: The patient underwent a craniotomy for cavernous angioma resection. Purulent material was noted at the time of resection, and no hemorrhage was observed. Despite antibiotic therapy, the patient required repeat craniotomies for subsequent abscess treatment. M. hominis was identified as the pathogen. CONCLUSION: M. hominis is a rare cause of brain abscesses and can be difficult to eradicate. Cavernous angiomas can be seeded hematogenously.

Adult↗

PubMed2003

Preoperative sestamibi localization combined with intraoperative parathyroid hormone assay predicts successful focused unilateral neck exploration during surgery for primary hyperparathyroidism.

A retrospective review of 54 cases of primary hyperparathyroidism operated upon by five general surgeons at Santa Barbara Cottage Hospital between March 1998 and March 2001 was performed to determine whether positive preoperative sestamibi localization (PSL) of a solitary adenoma combined with intraoperative parathyroid hormone assay (IOPHA) could predict successful focused unilateral neck exploration. A solitary adenoma was found in each of 50 patients (93%). PSL for solitary adenomas had an accuracy of 87 per cent, positive predictive value (PPV) of 96 per cent, sensitivity of 90 per cent, and specificity of 50 per cent. Forty-five patients (83%) achieved a 50 per cent reduction in IOPHA at 10 minutes after excision of a solitary adenoma for an accuracy of 85 per cent, PPV of 97 per cent, sensitivity of 88 per cent, and specificity of 50 per cent. All patients remain eucalcemic. The combination of PSL and IOPHA resulted in a PPV of 97.5 per cent and a sensitivity of 100 per cent. From these data we conclude that a focused unilateral neck exploration could have been performed successfully in 78 per cent of the cases.

Adenoma↗